From 39203d59b7f4dc4cce48b21f14ad480927503934 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Thu, 22 Dec 2022 08:41:53 -0500
Subject: [PATCH 01/40] update default registration for load_earth_relief

---
 pygmt/datasets/load_remote_dataset.py     | 38 ++++++++++++-----------
 pygmt/tests/test_datasets_earth_relief.py |  5 ++-
 2 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/pygmt/datasets/load_remote_dataset.py b/pygmt/datasets/load_remote_dataset.py
index aec1ac6fd8a..2b80f8823a5 100644
--- a/pygmt/datasets/load_remote_dataset.py
+++ b/pygmt/datasets/load_remote_dataset.py
@@ -71,18 +71,18 @@ class GMTRemoteDataset(NamedTuple):
         units="meters",
         extra_attributes={"vertical_datum": "EGM96", "horizontal_datum": "WGS84"},
         resolutions={
-            "01d": Resolution(["pixel", "gridline"], False),
-            "30m": Resolution(["pixel", "gridline"], False),
-            "20m": Resolution(["pixel", "gridline"], False),
-            "15m": Resolution(["pixel", "gridline"], False),
-            "10m": Resolution(["pixel", "gridline"], False),
-            "06m": Resolution(["pixel", "gridline"], False),
-            "05m": Resolution(["pixel", "gridline"], True),
-            "04m": Resolution(["pixel", "gridline"], True),
-            "03m": Resolution(["pixel", "gridline"], True),
-            "02m": Resolution(["pixel", "gridline"], True),
-            "01m": Resolution(["pixel", "gridline"], True),
-            "30s": Resolution(["pixel", "gridline"], True),
+            "01d": Resolution(["gridline", "pixel"], False),
+            "30m": Resolution(["gridline", "pixel"], False),
+            "20m": Resolution(["gridline", "pixel"], False),
+            "15m": Resolution(["gridline", "pixel"], False),
+            "10m": Resolution(["gridline", "pixel"], False),
+            "06m": Resolution(["gridline", "pixel"], False),
+            "05m": Resolution(["gridline", "pixel"], True),
+            "04m": Resolution(["gridline", "pixel"], True),
+            "03m": Resolution(["gridline", "pixel"], True),
+            "02m": Resolution(["gridline", "pixel"], True),
+            "01m": Resolution(["gridline", "pixel"], True),
+            "30s": Resolution(["gridline", "pixel"], True),
             "15s": Resolution(["pixel"], True),
             "03s": Resolution(["gridline"], True),
             "01s": Resolution(["gridline"], True),
@@ -210,10 +210,14 @@ def _load_remote_dataset(
     The returned :class:`xarray.DataArray` doesn't support slice operation for
     tiled grids.
     """
-
-    if registration in ("pixel", "gridline", None):
+    dataset = datasets[dataset_name]
+    if resolution not in dataset.resolutions.keys():
+        raise GMTInvalidInput(f"Invalid resolution '{resolution}'.")
+    if registration is None:
+        registration = dataset.resolutions[resolution].registrations[0]
+    if registration in ("pixel", "gridline"):
         # If None, let GMT decide on Pixel/Gridline type
-        reg = f"_{registration[0]}" if registration else ""
+        reg = f"_{registration[0]}"
     else:
         raise GMTInvalidInput(
             f"Invalid grid registration: '{registration}', should be either "
@@ -221,9 +225,7 @@ def _load_remote_dataset(
             "pixel-registered grid is returned unless only the "
             "gridline-registered grid is available."
         )
-    dataset = datasets[dataset_name]
-    if resolution not in dataset.resolutions.keys():
-        raise GMTInvalidInput(f"Invalid resolution '{resolution}'.")
+
     if registration and (
         registration not in dataset.resolutions[resolution].registrations
     ):
diff --git a/pygmt/tests/test_datasets_earth_relief.py b/pygmt/tests/test_datasets_earth_relief.py
index 5e6bfe02247..27615aa901c 100644
--- a/pygmt/tests/test_datasets_earth_relief.py
+++ b/pygmt/tests/test_datasets_earth_relief.py
@@ -27,14 +27,13 @@ def test_earth_relief_01d_igpp_synbath(data_source):
     Test some properties of the earth relief 01d data with IGPP and SYNBATH
     data.
     """
-    data = load_earth_relief(
-        resolution="01d", registration="gridline", data_source=data_source
-    )
+    data = load_earth_relief(resolution="01d", data_source=data_source)
     assert data.name == "elevation"
     assert data.attrs["units"] == "meters"
     assert data.attrs["long_name"] == "Earth elevation relative to the geoid"
     assert data.attrs["vertical_datum"] == "EGM96"
     assert data.attrs["horizontal_datum"] == "WGS84"
+    assert data.gmt.registration == 0
     assert data.shape == (181, 361)
     npt.assert_allclose(data.lat, np.arange(-90, 91, 1))
     npt.assert_allclose(data.lon, np.arange(-180, 181, 1))

From dd1b68544929e8f3c3ca82bb8f6d2e8e2f9be5bb Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Thu, 22 Dec 2022 08:45:03 -0500
Subject: [PATCH 02/40] update default registration for load_earth_age

---
 pygmt/datasets/load_remote_dataset.py     | 20 ++++++++++----------
 pygmt/tests/test_datasets_earth_age.py    |  4 +++-
 pygmt/tests/test_datasets_earth_relief.py |  1 +
 3 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/pygmt/datasets/load_remote_dataset.py b/pygmt/datasets/load_remote_dataset.py
index 2b80f8823a5..fc3dd90a666 100644
--- a/pygmt/datasets/load_remote_dataset.py
+++ b/pygmt/datasets/load_remote_dataset.py
@@ -95,16 +95,16 @@ class GMTRemoteDataset(NamedTuple):
         units="Myr",
         extra_attributes={"horizontal_datum": "WGS84"},
         resolutions={
-            "01d": Resolution(["pixel", "gridline"], False),
-            "30m": Resolution(["pixel", "gridline"], False),
-            "20m": Resolution(["pixel", "gridline"], False),
-            "15m": Resolution(["pixel", "gridline"], False),
-            "10m": Resolution(["pixel", "gridline"], False),
-            "06m": Resolution(["pixel", "gridline"], False),
-            "05m": Resolution(["pixel", "gridline"], True),
-            "04m": Resolution(["pixel", "gridline"], True),
-            "03m": Resolution(["pixel", "gridline"], True),
-            "02m": Resolution(["pixel", "gridline"], True),
+            "01d": Resolution(["gridline", "pixel"], False),
+            "30m": Resolution(["gridline", "pixel"], False),
+            "20m": Resolution(["gridline", "pixel"], False),
+            "15m": Resolution(["gridline", "pixel"], False),
+            "10m": Resolution(["gridline", "pixel"], False),
+            "06m": Resolution(["gridline", "pixel"], False),
+            "05m": Resolution(["gridline", "pixel"], True),
+            "04m": Resolution(["gridline", "pixel"], True),
+            "03m": Resolution(["gridline", "pixel"], True),
+            "02m": Resolution(["gridline", "pixel"], True),
             "01m": Resolution(["gridline"], True),
         },
     ),
diff --git a/pygmt/tests/test_datasets_earth_age.py b/pygmt/tests/test_datasets_earth_age.py
index a3ebfdba409..70f648cc64a 100644
--- a/pygmt/tests/test_datasets_earth_age.py
+++ b/pygmt/tests/test_datasets_earth_age.py
@@ -31,12 +31,13 @@ def test_earth_age_01d():
     """
     Test some properties of the earth age 01d data.
     """
-    data = load_earth_age(resolution="01d", registration="gridline")
+    data = load_earth_age(resolution="01d")
     assert data.name == "seafloor_age"
     assert data.attrs["units"] == "Myr"
     assert data.attrs["long_name"] == "age of seafloor crust"
     assert data.attrs["horizontal_datum"] == "WGS84"
     assert data.shape == (181, 361)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-90, 91, 1))
     npt.assert_allclose(data.lon, np.arange(-180, 181, 1))
     npt.assert_allclose(data.min(), 0.167381, rtol=1e-5)
@@ -51,6 +52,7 @@ def test_earth_age_01d_with_region():
         resolution="01d", region=[-10, 10, -5, 5], registration="gridline"
     )
     assert data.shape == (11, 21)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-5, 6, 1))
     npt.assert_allclose(data.lon, np.arange(-10, 11, 1))
     npt.assert_allclose(data.min(), 11.293945)
diff --git a/pygmt/tests/test_datasets_earth_relief.py b/pygmt/tests/test_datasets_earth_relief.py
index 27615aa901c..7079803c5a4 100644
--- a/pygmt/tests/test_datasets_earth_relief.py
+++ b/pygmt/tests/test_datasets_earth_relief.py
@@ -131,6 +131,7 @@ def test_earth_gebcosi_15m_with_region():
         data_source="gebcosi",
     )
     assert data.shape == (16, 8)
+    assert data.gmt.registration == 1
     npt.assert_allclose(data.lat, np.arange(-87.875, -84, 0.25))
     npt.assert_allclose(data.lon, np.arange(85.125, 87, 0.25))
     npt.assert_allclose(data.min(), -531)

From 5d649e644bf6d23f1dba5383b7306ec7f70d7649 Mon Sep 17 00:00:00 2001
From: Dongdong Tian <seisman.info@gmail.com>
Date: Mon, 26 Dec 2022 23:05:30 +0800
Subject: [PATCH 03/40] Update pygmt/datasets/load_remote_dataset.py

---
 pygmt/datasets/load_remote_dataset.py | 24 ------------------------
 1 file changed, 24 deletions(-)

diff --git a/pygmt/datasets/load_remote_dataset.py b/pygmt/datasets/load_remote_dataset.py
index 978db2a359f..43c9c8f9851 100644
--- a/pygmt/datasets/load_remote_dataset.py
+++ b/pygmt/datasets/load_remote_dataset.py
@@ -64,30 +64,6 @@ class GMTRemoteDataset(NamedTuple):
 
 
 datasets = {
-    "earth_relief": GMTRemoteDataset(
-        title="Earth relief",
-        name="elevation",
-        long_name="Earth elevation relative to the geoid",
-        units="meters",
-        extra_attributes={"vertical_datum": "EGM96", "horizontal_datum": "WGS84"},
-        resolutions={
-            "01d": Resolution(["gridline", "pixel"], False),
-            "30m": Resolution(["gridline", "pixel"], False),
-            "20m": Resolution(["gridline", "pixel"], False),
-            "15m": Resolution(["gridline", "pixel"], False),
-            "10m": Resolution(["gridline", "pixel"], False),
-            "06m": Resolution(["gridline", "pixel"], False),
-            "05m": Resolution(["gridline", "pixel"], True),
-            "04m": Resolution(["gridline", "pixel"], True),
-            "03m": Resolution(["gridline", "pixel"], True),
-            "02m": Resolution(["gridline", "pixel"], True),
-            "01m": Resolution(["gridline", "pixel"], True),
-            "30s": Resolution(["gridline", "pixel"], True),
-            "15s": Resolution(["pixel"], True),
-            "03s": Resolution(["gridline"], True),
-            "01s": Resolution(["gridline"], True),
-        },
-    ),
     "earth_age": GMTRemoteDataset(
         title="seafloor age",
         name="seafloor_age",

From 24b8931b5f255f805f2961c804c188b780540b3d Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 06:30:22 -0500
Subject: [PATCH 04/40] change if statement for default registration

---
 pygmt/datasets/load_remote_dataset.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/pygmt/datasets/load_remote_dataset.py b/pygmt/datasets/load_remote_dataset.py
index 43c9c8f9851..20f22e70570 100644
--- a/pygmt/datasets/load_remote_dataset.py
+++ b/pygmt/datasets/load_remote_dataset.py
@@ -234,7 +234,12 @@ def _load_remote_dataset(
     if resolution not in dataset.resolutions.keys():
         raise GMTInvalidInput(f"Invalid resolution '{resolution}'.")
     if registration is None:
-        registration = dataset.resolutions[resolution].registrations[0]
+        # Check if "gridline" is an available registration for the resolution
+        if "gridline" in dataset.resolutions[resolution].registrations:
+            # Use default of gridline registration if available
+            registration = "gridline"
+        else:
+            registration = "pixel"
     if registration in ("pixel", "gridline"):
         # If None, let GMT decide on Pixel/Gridline type
         reg = f"_{registration[0]}"

From bdfc550f15c1b43e044e229db8ef190ffb92d2fc Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 06:45:17 -0500
Subject: [PATCH 05/40] add default registration testing for
 test_datasets_earth_age.py

---
 pygmt/datasets/load_remote_dataset.py  |  1 -
 pygmt/helpers/testing.py               |  1 +
 pygmt/tests/test_datasets_earth_age.py | 16 ++++++++++++++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/pygmt/datasets/load_remote_dataset.py b/pygmt/datasets/load_remote_dataset.py
index 20f22e70570..4855896917e 100644
--- a/pygmt/datasets/load_remote_dataset.py
+++ b/pygmt/datasets/load_remote_dataset.py
@@ -241,7 +241,6 @@ def _load_remote_dataset(
         else:
             registration = "pixel"
     if registration in ("pixel", "gridline"):
-        # If None, let GMT decide on Pixel/Gridline type
         reg = f"_{registration[0]}"
     else:
         raise GMTInvalidInput(
diff --git a/pygmt/helpers/testing.py b/pygmt/helpers/testing.py
index 06eb3af0482..78111092960 100644
--- a/pygmt/helpers/testing.py
+++ b/pygmt/helpers/testing.py
@@ -180,6 +180,7 @@ def download_test_data():
         # Earth seafloor age grids
         "@earth_age_01d_g",
         "@S90W180.earth_age_05m_g.nc",  # Specific grid for 05m test
+        "@N00W030.earth_age_01m_g.nc",  # Specific grid for 01m test
         # Earth geoid grids
         "@earth_geoid_01d_g",
         "@S90W180.earth_geoid_05m_g.nc",  # Specific grid for 05m test
diff --git a/pygmt/tests/test_datasets_earth_age.py b/pygmt/tests/test_datasets_earth_age.py
index 70f648cc64a..259cfde638e 100644
--- a/pygmt/tests/test_datasets_earth_age.py
+++ b/pygmt/tests/test_datasets_earth_age.py
@@ -91,3 +91,19 @@ def test_earth_age_incorrect_resolution_registration():
     """
     with pytest.raises(GMTInvalidInput):
         load_earth_age(resolution="01m", region=[0, 1, 3, 5], registration="pixel")
+
+def test_earth_age_01m_default_registration():
+    """
+    Test that the grid returned by default for the 1 arc-minute resolution
+    has a "gridline" registration.
+    """
+    data = load_earth_age(resolution="01m", region=[-10, -9, 3, 5])
+    assert data.shape == (121, 61)
+    assert data.gmt.registration == 0
+    assert data.coords["lat"].data.min() == 3.0
+    assert data.coords["lat"].data.max() == 5.0
+    assert data.coords["lon"].data.min() == -10.0
+    assert data.coords["lon"].data.max() == -9.0
+    npt.assert_allclose(data.min(), 88.63)
+    npt.assert_allclose(data.max(), 125.25)
+

From 7b0a219c402f0d52b0d80ef78df57608c659ea7d Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 06:47:47 -0500
Subject: [PATCH 06/40] update earth_age registration docstring

---
 pygmt/datasets/earth_age.py | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/pygmt/datasets/earth_age.py b/pygmt/datasets/earth_age.py
index 8b0fc50ec4e..43cee8341d7 100644
--- a/pygmt/datasets/earth_age.py
+++ b/pygmt/datasets/earth_age.py
@@ -44,9 +44,8 @@ def load_earth_age(resolution="01d", region=None, registration=None):
 
     registration : str
         Grid registration type. Either ``"pixel"`` for pixel registration or
-        ``"gridline"`` for gridline registration. Default is ``None``, where
-        a pixel-registered grid is returned unless only the
-        gridline-registered grid is available.
+        ``"gridline"`` for gridline registration. Default is ``"gridline"``
+        when available.
 
     Returns
     -------

From 2fefe641c8a92bfde0e46b774c1b9e116cd16bdf Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 06:57:20 -0500
Subject: [PATCH 07/40] update earth_free_air_anomaly registration docstring

---
 pygmt/datasets/earth_free_air_anomaly.py | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/pygmt/datasets/earth_free_air_anomaly.py b/pygmt/datasets/earth_free_air_anomaly.py
index afc94a4bbdf..d35497b3306 100644
--- a/pygmt/datasets/earth_free_air_anomaly.py
+++ b/pygmt/datasets/earth_free_air_anomaly.py
@@ -44,9 +44,8 @@ def load_earth_free_air_anomaly(resolution="01d", region=None, registration=None
 
     registration : str
         Grid registration type. Either ``"pixel"`` for pixel registration or
-        ``"gridline"`` for gridline registration. Default is ``None``, where
-        a pixel-registered grid is returned unless only the
-        gridline-registered grid is available.
+        ``"gridline"`` for gridline registration. Default is ``"gridline"``
+        when available.
 
     Returns
     -------

From 3442893a3b396589737b64719ef3072c51a1278f Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 06:58:51 -0500
Subject: [PATCH 08/40] update test_datasets_earth_free_air_anomaly.py for
 default registration

---
 pygmt/helpers/testing.py                          |  1 +
 .../tests/test_datasets_earth_free_air_anomaly.py | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/pygmt/helpers/testing.py b/pygmt/helpers/testing.py
index 78111092960..dfff6983a85 100644
--- a/pygmt/helpers/testing.py
+++ b/pygmt/helpers/testing.py
@@ -192,6 +192,7 @@ def download_test_data():
         # Earth free-air anomaly grids
         "@earth_faa_01d_g",
         "@S90W180.earth_faa_05m_g.nc",  # Specific grid for 05m test
+        "@N00W030.earth_faa_01m_g.nc",  # Specific grid for 01m test
         # Earth vertical gravity gradient grids
         "@earth_vgg_01d_g",
         "@S90W180.earth_vgg_05m_g.nc",  # Specific grid for 05m test
diff --git a/pygmt/tests/test_datasets_earth_free_air_anomaly.py b/pygmt/tests/test_datasets_earth_free_air_anomaly.py
index f2351e24c11..c4e566dfda9 100644
--- a/pygmt/tests/test_datasets_earth_free_air_anomaly.py
+++ b/pygmt/tests/test_datasets_earth_free_air_anomaly.py
@@ -80,3 +80,18 @@ def test_earth_faa_05m_without_region():
     """
     with pytest.raises(GMTInvalidInput):
         load_earth_free_air_anomaly("05m")
+
+def test_earth_age_01m_default_registration():
+    """
+    Test that the grid returned by default for the 1 arc-minute resolution
+    has a "pixel" registration.
+    """
+    data = load_earth_free_air_anomaly(resolution="01m", region=[-10, -9, 3, 5])
+    assert data.shape == (120, 60)
+    assert data.gmt.registration == 1
+    npt.assert_allclose(data.coords["lat"].data.min(), 3.008333333)
+    npt.assert_allclose(data.coords["lat"].data.max(), 4.991666666)
+    npt.assert_allclose(data.coords["lon"].data.min(), -9.99166666)
+    npt.assert_allclose(data.coords["lon"].data.max(), -9.00833333)
+    npt.assert_allclose(data.min(), -51)
+    npt.assert_allclose(data.max(), 113.675)

From d36f53d5e814ed5fbba7db4dacf364af6b1b778f Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 07:05:37 -0500
Subject: [PATCH 09/40] update registration docstring in earth_geoid.py

---
 pygmt/datasets/earth_geoid.py | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/pygmt/datasets/earth_geoid.py b/pygmt/datasets/earth_geoid.py
index 87228ef771b..5025e7383fe 100644
--- a/pygmt/datasets/earth_geoid.py
+++ b/pygmt/datasets/earth_geoid.py
@@ -44,9 +44,8 @@ def load_earth_geoid(resolution="01d", region=None, registration=None):
 
     registration : str
         Grid registration type. Either ``"pixel"`` for pixel registration or
-        ``"gridline"`` for gridline registration. Default is ``None``, where
-        a pixel-registered grid is returned unless only the
-        gridline-registered grid is available.
+        ``"gridline"`` for gridline registration. Default is ``"gridline"``
+        when available.
 
     Returns
     -------

From 24b3e73a73afa9e51eba6a65beaa0ebd7515a3b8 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 07:11:04 -0500
Subject: [PATCH 10/40] add test to test_datasets_earth_geoid.py for default
 registration

---
 pygmt/helpers/testing.py                         |  1 +
 .../test_datasets_earth_free_air_anomaly.py      |  2 +-
 pygmt/tests/test_datasets_earth_geoid.py         | 16 ++++++++++++++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/pygmt/helpers/testing.py b/pygmt/helpers/testing.py
index dfff6983a85..8e0c4ca6e42 100644
--- a/pygmt/helpers/testing.py
+++ b/pygmt/helpers/testing.py
@@ -184,6 +184,7 @@ def download_test_data():
         # Earth geoid grids
         "@earth_geoid_01d_g",
         "@S90W180.earth_geoid_05m_g.nc",  # Specific grid for 05m test
+        "@N00W030.earth_geoid_01m_g.nc",  # Specific grid for 01m test
         # Earth magnetic anomaly grids
         "@earth_mag_01d_g",
         "@S90W180.earth_mag_05m_g.nc",  # Specific grid for 05m test
diff --git a/pygmt/tests/test_datasets_earth_free_air_anomaly.py b/pygmt/tests/test_datasets_earth_free_air_anomaly.py
index c4e566dfda9..3ae5bf9f06f 100644
--- a/pygmt/tests/test_datasets_earth_free_air_anomaly.py
+++ b/pygmt/tests/test_datasets_earth_free_air_anomaly.py
@@ -81,7 +81,7 @@ def test_earth_faa_05m_without_region():
     with pytest.raises(GMTInvalidInput):
         load_earth_free_air_anomaly("05m")
 
-def test_earth_age_01m_default_registration():
+def test_earth_faa_01m_default_registration():
     """
     Test that the grid returned by default for the 1 arc-minute resolution
     has a "pixel" registration.
diff --git a/pygmt/tests/test_datasets_earth_geoid.py b/pygmt/tests/test_datasets_earth_geoid.py
index 281a5a957d9..a88089301ca 100644
--- a/pygmt/tests/test_datasets_earth_geoid.py
+++ b/pygmt/tests/test_datasets_earth_geoid.py
@@ -89,3 +89,19 @@ def test_earth_geoid_incorrect_resolution_registration():
     """
     with pytest.raises(GMTInvalidInput):
         load_earth_geoid(resolution="01m", region=[0, 1, 3, 5], registration="pixel")
+
+def test_earth_geoid_01m_default_registration():
+    """
+    Test that the grid returned by default for the 1 arc-minute resolution
+    has a "gridline" registration.
+    """
+    data = load_earth_geoid(resolution="01m", region=[-10, -9, 3, 5])
+    assert data.shape == (121, 61)
+    assert data.gmt.registration == 0
+    assert data.coords["lat"].data.min() == 3.0
+    assert data.coords["lat"].data.max() == 5.0
+    assert data.coords["lon"].data.min() == -10.0
+    assert data.coords["lon"].data.max() == -9.0
+    npt.assert_allclose(data.min(), 20.34)
+    npt.assert_allclose(data.max(), 30.039999)
+

From 2a64cf5dbe707ea176de18785b87e4b7701fbcda Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 07:12:13 -0500
Subject: [PATCH 11/40] update registration docstring in
 earth_magnetic_anomaly.py

---
 pygmt/datasets/earth_magnetic_anomaly.py | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/pygmt/datasets/earth_magnetic_anomaly.py b/pygmt/datasets/earth_magnetic_anomaly.py
index c7d010acf6b..629c5ba974e 100644
--- a/pygmt/datasets/earth_magnetic_anomaly.py
+++ b/pygmt/datasets/earth_magnetic_anomaly.py
@@ -49,9 +49,8 @@ def load_earth_magnetic_anomaly(
 
     registration : str
         Grid registration type. Either ``"pixel"`` for pixel registration or
-        ``"gridline"`` for gridline registration. Default is ``None``, where
-        a pixel-registered grid is returned unless only the
-        gridline-registered grid is available.
+        ``"gridline"`` for gridline registration. Default is ``"gridline"``
+        when available.
 
     mag4km : bool
         Choose the data version to use. The default is ``False``, which is

From eaa57aed892326e33e55c17599bd856e07cd95cd Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 07:25:33 -0500
Subject: [PATCH 12/40] add test to test_datasets_earth_magnetic_anomaly.py for
 default registration

---
 pygmt/helpers/testing.py                          |  1 +
 .../tests/test_datasets_earth_magnetic_anomaly.py | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/pygmt/helpers/testing.py b/pygmt/helpers/testing.py
index 8e0c4ca6e42..35c448ec5e3 100644
--- a/pygmt/helpers/testing.py
+++ b/pygmt/helpers/testing.py
@@ -188,6 +188,7 @@ def download_test_data():
         # Earth magnetic anomaly grids
         "@earth_mag_01d_g",
         "@S90W180.earth_mag_05m_g.nc",  # Specific grid for 05m test
+        "@S30W060.earth_mag_02m_p.nc",  # Specific grid for 02m test
         "@earth_mag4km_01d_g",
         "@S90W180.earth_mag4km_05m_g.nc",  # Specific grid for 05m test
         # Earth free-air anomaly grids
diff --git a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
index 6c2f939ab55..b5ac9833f03 100644
--- a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
+++ b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
@@ -146,3 +146,18 @@ def test_earth_mag4km_05m_with_region():
     assert data.lon.max() == -112
     npt.assert_allclose(data.min(), -128.40015)
     npt.assert_allclose(data.max(), 76.80005)
+
+def test_earth_mag_02m_default_registration():
+    """
+    Test that the grid returned by default for the 2 arc-minute resolution
+    has a "pixel" registration.
+    """
+    data = load_earth_magnetic_anomaly(resolution="02m", region=[-10, -9, 3, 5])
+    assert data.shape == (60, 30)
+    assert data.gmt.registration == 1
+    npt.assert_allclose(data.coords["lat"].data.min(), 3.016666667)
+    npt.assert_allclose(data.coords["lat"].data.max(), 4.983333333)
+    npt.assert_allclose(data.coords["lon"].data.min(), -9.98333333)
+    npt.assert_allclose(data.coords["lon"].data.max(), -9.01666667)
+    npt.assert_allclose(data.min(), -231)
+    npt.assert_allclose(data.max(), 131.79999)

From 040883e568054bc37316c30ef774c0827b6d23e9 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 07:27:26 -0500
Subject: [PATCH 13/40] update registration docstring in
 earth_vertical_gravity_gradient.py

---
 pygmt/datasets/earth_vertical_gravity_gradient.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/pygmt/datasets/earth_vertical_gravity_gradient.py b/pygmt/datasets/earth_vertical_gravity_gradient.py
index b47daad94c7..62b9dd2c802 100644
--- a/pygmt/datasets/earth_vertical_gravity_gradient.py
+++ b/pygmt/datasets/earth_vertical_gravity_gradient.py
@@ -45,9 +45,9 @@ def load_earth_vertical_gravity_gradient(
 
     registration : str
         Grid registration type. Either ``"pixel"`` for pixel registration or
-        ``"gridline"`` for gridline registration. Default is ``None``, where
-        a pixel-registered grid is returned unless only the
-        gridline-registered grid is available.
+        ``"gridline"`` for gridline registration. Default is ``"gridline"``
+        when available.
+
 
     Returns
     -------

From 79ca10e763f06c6587ad6b65160b241262e4c723 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 07:27:53 -0500
Subject: [PATCH 14/40] run make format

---
 pygmt/tests/test_datasets_earth_age.py              | 6 +++---
 pygmt/tests/test_datasets_earth_free_air_anomaly.py | 5 +++--
 pygmt/tests/test_datasets_earth_geoid.py            | 6 +++---
 pygmt/tests/test_datasets_earth_magnetic_anomaly.py | 5 +++--
 4 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/pygmt/tests/test_datasets_earth_age.py b/pygmt/tests/test_datasets_earth_age.py
index 259cfde638e..1654b63e504 100644
--- a/pygmt/tests/test_datasets_earth_age.py
+++ b/pygmt/tests/test_datasets_earth_age.py
@@ -92,10 +92,11 @@ def test_earth_age_incorrect_resolution_registration():
     with pytest.raises(GMTInvalidInput):
         load_earth_age(resolution="01m", region=[0, 1, 3, 5], registration="pixel")
 
+
 def test_earth_age_01m_default_registration():
     """
-    Test that the grid returned by default for the 1 arc-minute resolution
-    has a "gridline" registration.
+    Test that the grid returned by default for the 1 arc-minute resolution has
+    a "gridline" registration.
     """
     data = load_earth_age(resolution="01m", region=[-10, -9, 3, 5])
     assert data.shape == (121, 61)
@@ -106,4 +107,3 @@ def test_earth_age_01m_default_registration():
     assert data.coords["lon"].data.max() == -9.0
     npt.assert_allclose(data.min(), 88.63)
     npt.assert_allclose(data.max(), 125.25)
-
diff --git a/pygmt/tests/test_datasets_earth_free_air_anomaly.py b/pygmt/tests/test_datasets_earth_free_air_anomaly.py
index 3ae5bf9f06f..8c26bae533f 100644
--- a/pygmt/tests/test_datasets_earth_free_air_anomaly.py
+++ b/pygmt/tests/test_datasets_earth_free_air_anomaly.py
@@ -81,10 +81,11 @@ def test_earth_faa_05m_without_region():
     with pytest.raises(GMTInvalidInput):
         load_earth_free_air_anomaly("05m")
 
+
 def test_earth_faa_01m_default_registration():
     """
-    Test that the grid returned by default for the 1 arc-minute resolution
-    has a "pixel" registration.
+    Test that the grid returned by default for the 1 arc-minute resolution has
+    a "pixel" registration.
     """
     data = load_earth_free_air_anomaly(resolution="01m", region=[-10, -9, 3, 5])
     assert data.shape == (120, 60)
diff --git a/pygmt/tests/test_datasets_earth_geoid.py b/pygmt/tests/test_datasets_earth_geoid.py
index a88089301ca..2d76fa67d9a 100644
--- a/pygmt/tests/test_datasets_earth_geoid.py
+++ b/pygmt/tests/test_datasets_earth_geoid.py
@@ -90,10 +90,11 @@ def test_earth_geoid_incorrect_resolution_registration():
     with pytest.raises(GMTInvalidInput):
         load_earth_geoid(resolution="01m", region=[0, 1, 3, 5], registration="pixel")
 
+
 def test_earth_geoid_01m_default_registration():
     """
-    Test that the grid returned by default for the 1 arc-minute resolution
-    has a "gridline" registration.
+    Test that the grid returned by default for the 1 arc-minute resolution has
+    a "gridline" registration.
     """
     data = load_earth_geoid(resolution="01m", region=[-10, -9, 3, 5])
     assert data.shape == (121, 61)
@@ -104,4 +105,3 @@ def test_earth_geoid_01m_default_registration():
     assert data.coords["lon"].data.max() == -9.0
     npt.assert_allclose(data.min(), 20.34)
     npt.assert_allclose(data.max(), 30.039999)
-
diff --git a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
index b5ac9833f03..00b2b896eb5 100644
--- a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
+++ b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
@@ -147,10 +147,11 @@ def test_earth_mag4km_05m_with_region():
     npt.assert_allclose(data.min(), -128.40015)
     npt.assert_allclose(data.max(), 76.80005)
 
+
 def test_earth_mag_02m_default_registration():
     """
-    Test that the grid returned by default for the 2 arc-minute resolution
-    has a "pixel" registration.
+    Test that the grid returned by default for the 2 arc-minute resolution has
+    a "pixel" registration.
     """
     data = load_earth_magnetic_anomaly(resolution="02m", region=[-10, -9, 3, 5])
     assert data.shape == (60, 30)

From 664d7daa84f2cbdbfedcac73d2cc95752cf13ace Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 07:35:42 -0500
Subject: [PATCH 15/40] add test for default registration to
 test_datasets_earth_vertical_gravity_gradient.py

---
 pygmt/helpers/testing.py                       |  3 ++-
 ...datasets_earth_vertical_gravity_gradient.py | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/pygmt/helpers/testing.py b/pygmt/helpers/testing.py
index 35c448ec5e3..759754cc3ae 100644
--- a/pygmt/helpers/testing.py
+++ b/pygmt/helpers/testing.py
@@ -194,10 +194,11 @@ def download_test_data():
         # Earth free-air anomaly grids
         "@earth_faa_01d_g",
         "@S90W180.earth_faa_05m_g.nc",  # Specific grid for 05m test
-        "@N00W030.earth_faa_01m_g.nc",  # Specific grid for 01m test
+        "@N00W030.earth_faa_01m_p.nc",  # Specific grid for 01m test
         # Earth vertical gravity gradient grids
         "@earth_vgg_01d_g",
         "@S90W180.earth_vgg_05m_g.nc",  # Specific grid for 05m test
+        "@N00W030.earth_vgg_01m_p.nc",  # Specific grid for 01m test
         # Other cache files
         "@capitals.gmt",
         "@earth_relief_20m_holes.grd",
diff --git a/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py b/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py
index 2bbb85764d5..2030b909803 100644
--- a/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py
+++ b/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py
@@ -96,3 +96,21 @@ def test_earth_vertical_gravity_gradient_incorrect_resolution_registration():
         load_earth_vertical_gravity_gradient(
             resolution="01m", region=[0, 1, 3, 5], registration="gridline"
         )
+
+
+def test_earth_vertical_gravity_gradient_01m_default_registration():
+    """
+    Test that the grid returned by default for the 1 arc-minute resolution has
+    a "pixel" registration.
+    """
+    data = load_earth_vertical_gravity_gradient(
+        resolution="01m", region=[-10, -9, 3, 5]
+    )
+    assert data.shape == (120, 60)
+    assert data.gmt.registration == 1
+    npt.assert_allclose(data.coords["lat"].data.min(), 3.008333333)
+    npt.assert_allclose(data.coords["lat"].data.max(), 4.991666666)
+    npt.assert_allclose(data.coords["lon"].data.min(), -9.99166666)
+    npt.assert_allclose(data.coords["lon"].data.max(), -9.00833333)
+    npt.assert_allclose(data.min(), -40.25)
+    npt.assert_allclose(data.max(), 81.75)

From c7fa8f5c3e818ed16ac268ff4593fbf1a023d0ca Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 07:37:21 -0500
Subject: [PATCH 16/40] update registration docstring to earth_relief.py

---
 pygmt/datasets/earth_relief.py | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/pygmt/datasets/earth_relief.py b/pygmt/datasets/earth_relief.py
index fe8937492a9..a712c8b0ec8 100644
--- a/pygmt/datasets/earth_relief.py
+++ b/pygmt/datasets/earth_relief.py
@@ -57,9 +57,8 @@ def load_earth_relief(
 
     registration : str
         Grid registration type. Either ``"pixel"`` for pixel registration or
-        ``"gridline"`` for gridline registration. Default is ``None``, where
-        a gridline-registered grid is returned unless only the pixel-registered
-        grid is available.
+        ``"gridline"`` for gridline registration. Default is ``"gridline"``
+        when available.
 
         **Note**: For GMT 6.3, ``registration=None`` returns a pixel-registered
         grid by default unless only the gridline-registered grid is available.

From 7ec384da43841cb643c88321735fc15b6a360679 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 07:37:51 -0500
Subject: [PATCH 17/40] remove note in earth_relief.py

---
 pygmt/datasets/earth_relief.py | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/pygmt/datasets/earth_relief.py b/pygmt/datasets/earth_relief.py
index a712c8b0ec8..7a2ea6c3115 100644
--- a/pygmt/datasets/earth_relief.py
+++ b/pygmt/datasets/earth_relief.py
@@ -60,9 +60,6 @@ def load_earth_relief(
         ``"gridline"`` for gridline registration. Default is ``"gridline"``
         when available.
 
-        **Note**: For GMT 6.3, ``registration=None`` returns a pixel-registered
-        grid by default unless only the gridline-registered grid is available.
-
     data_source : str
         Select the source for the Earth relief data.
 

From 1fadc26cef8295c98f6e4e68560ea54d7194e1bd Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 08:10:57 -0500
Subject: [PATCH 18/40] add tests for loading default registrations for 15s and
 03s to test_datasets_earth_relief.py

---
 pygmt/helpers/testing.py                  |  2 ++
 pygmt/tests/test_datasets_earth_relief.py | 30 +++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/pygmt/helpers/testing.py b/pygmt/helpers/testing.py
index 759754cc3ae..7811076057b 100644
--- a/pygmt/helpers/testing.py
+++ b/pygmt/helpers/testing.py
@@ -175,6 +175,8 @@ def download_test_data():
         "@N37W120.earth_relief_03s_g.nc",
         "@N00W090.earth_relief_03m_p.nc",
         "@N00E135.earth_relief_30s_g.nc",
+        "@N00W010.earth_relief_15s_p.nc",  # Specific grid for 15s test
+        "@N04W010.earth_relief_03s_g.nc",  # Specific grid for 03s test
         # Earth synbath relief grids
         "@S15W105.earth_synbath_30s_p.nc",
         # Earth seafloor age grids
diff --git a/pygmt/tests/test_datasets_earth_relief.py b/pygmt/tests/test_datasets_earth_relief.py
index 7079803c5a4..44d410aa884 100644
--- a/pygmt/tests/test_datasets_earth_relief.py
+++ b/pygmt/tests/test_datasets_earth_relief.py
@@ -247,3 +247,33 @@ def test_earth_relief_incorrect_resolution_registration(data_source):
             registration="gridline",
             data_source=data_source,
         )
+
+def test_earth_relief_15s_default_registration():
+    """
+    Test that the grid returned by default for the 15 arc-second resolution has
+    a "pixel" registration.
+    """
+    data = load_earth_relief(resolution="15s", region=[-10, -9.5, 4, 5])
+    assert data.shape == (240, 120)
+    assert data.gmt.registration == 1
+    npt.assert_allclose(data.coords["lat"].data.min(), 4.002083)
+    npt.assert_allclose(data.coords["lat"].data.max(), 4.997917)
+    npt.assert_allclose(data.coords["lon"].data.min(), -9.997917)
+    npt.assert_allclose(data.coords["lon"].data.max(), -9.502083)
+    npt.assert_allclose(data.min(), -3897)
+    npt.assert_allclose(data.max(), -74)
+
+def test_earth_relief_03s_default_registration():
+    """
+    Test that the grid returned by default for the 3 arc-second resolution has
+    a "gridline" registration.
+    """
+    data = load_earth_relief(resolution="03s", region=[-10, -9.8, 4.9, 5])
+    assert data.shape == (121, 241)
+    assert data.gmt.registration == 0
+    npt.assert_allclose(data.coords["lat"].data.min(), 4.9)
+    npt.assert_allclose(data.coords["lat"].data.max(), 5)
+    npt.assert_allclose(data.coords["lon"].data.min(), -10)
+    npt.assert_allclose(data.coords["lon"].data.max(), -9.8)
+    npt.assert_allclose(data.min(), -2069.996)
+    npt.assert_allclose(data.max(), -924.0801)

From 6f306fdf55903b3eafbdd78dfcb8b055f4e1d5b2 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 08:11:29 -0500
Subject: [PATCH 19/40] run make format

---
 pygmt/tests/test_datasets_earth_relief.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pygmt/tests/test_datasets_earth_relief.py b/pygmt/tests/test_datasets_earth_relief.py
index 44d410aa884..e54c32f7321 100644
--- a/pygmt/tests/test_datasets_earth_relief.py
+++ b/pygmt/tests/test_datasets_earth_relief.py
@@ -248,6 +248,7 @@ def test_earth_relief_incorrect_resolution_registration(data_source):
             data_source=data_source,
         )
 
+
 def test_earth_relief_15s_default_registration():
     """
     Test that the grid returned by default for the 15 arc-second resolution has
@@ -263,6 +264,7 @@ def test_earth_relief_15s_default_registration():
     npt.assert_allclose(data.min(), -3897)
     npt.assert_allclose(data.max(), -74)
 
+
 def test_earth_relief_03s_default_registration():
     """
     Test that the grid returned by default for the 3 arc-second resolution has

From e24bcbca834079a8bd8ffa7e3ebcf90cdbb36deb Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 08:11:58 -0500
Subject: [PATCH 20/40] Update pygmt/datasets/load_remote_dataset.py

Co-authored-by: Dongdong Tian <seisman.info@gmail.com>
---
 pygmt/datasets/load_remote_dataset.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pygmt/datasets/load_remote_dataset.py b/pygmt/datasets/load_remote_dataset.py
index 4855896917e..c5953e1c727 100644
--- a/pygmt/datasets/load_remote_dataset.py
+++ b/pygmt/datasets/load_remote_dataset.py
@@ -246,8 +246,8 @@ def _load_remote_dataset(
         raise GMTInvalidInput(
             f"Invalid grid registration: '{registration}', should be either "
             "'pixel', 'gridline' or None. Default is None, where a "
-            "pixel-registered grid is returned unless only the "
-            "gridline-registered grid is available."
+            "gridline-registered grid is returned unless only the "
+            "pixel-registered grid is available."
         )
 
     if registration and (

From 087e6a9a222ce4394740bf1ec6b04b58e6837d67 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 10:07:38 -0500
Subject: [PATCH 21/40] remove test_earth_age_05m_with_region from
 test_datasets_earth_age.py

---
 pygmt/helpers/testing.py               |  1 -
 pygmt/tests/test_datasets_earth_age.py | 16 ----------------
 2 files changed, 17 deletions(-)

diff --git a/pygmt/helpers/testing.py b/pygmt/helpers/testing.py
index 7811076057b..0654ec105f0 100644
--- a/pygmt/helpers/testing.py
+++ b/pygmt/helpers/testing.py
@@ -181,7 +181,6 @@ def download_test_data():
         "@S15W105.earth_synbath_30s_p.nc",
         # Earth seafloor age grids
         "@earth_age_01d_g",
-        "@S90W180.earth_age_05m_g.nc",  # Specific grid for 05m test
         "@N00W030.earth_age_01m_g.nc",  # Specific grid for 01m test
         # Earth geoid grids
         "@earth_geoid_01d_g",
diff --git a/pygmt/tests/test_datasets_earth_age.py b/pygmt/tests/test_datasets_earth_age.py
index 1654b63e504..182425e860a 100644
--- a/pygmt/tests/test_datasets_earth_age.py
+++ b/pygmt/tests/test_datasets_earth_age.py
@@ -59,22 +59,6 @@ def test_earth_age_01d_with_region():
     npt.assert_allclose(data.max(), 125.1189)
 
 
-def test_earth_age_05m_with_region():
-    """
-    Test loading a subregion of high-resolution earth age.
-    """
-    data = load_earth_age(
-        resolution="05m", region=[-50, -40, 20, 30], registration="gridline"
-    )
-    assert data.coords["lat"].data.min() == 20.0
-    assert data.coords["lat"].data.max() == 30.0
-    assert data.coords["lon"].data.min() == -50.0
-    assert data.coords["lon"].data.max() == -40.0
-    npt.assert_allclose(data.data.min(), 0.040000916)
-    npt.assert_allclose(data.data.max(), 46.530003)
-    assert data.sizes["lat"] == 121
-    assert data.sizes["lon"] == 121
-
 
 def test_earth_age_05m_without_region():
     """

From 75519f7d75adc9140eead79e3c7e154f323c8088 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 10:08:49 -0500
Subject: [PATCH 22/40] remove test_earth_faa_05m_with_region from
 test_datasets_earth_free_air_anomaly.py

---
 pygmt/helpers/testing.py                         |  1 -
 pygmt/tests/test_datasets_earth_age.py           |  1 -
 .../test_datasets_earth_free_air_anomaly.py      | 16 ----------------
 3 files changed, 18 deletions(-)

diff --git a/pygmt/helpers/testing.py b/pygmt/helpers/testing.py
index 0654ec105f0..95512ec1dcb 100644
--- a/pygmt/helpers/testing.py
+++ b/pygmt/helpers/testing.py
@@ -194,7 +194,6 @@ def download_test_data():
         "@S90W180.earth_mag4km_05m_g.nc",  # Specific grid for 05m test
         # Earth free-air anomaly grids
         "@earth_faa_01d_g",
-        "@S90W180.earth_faa_05m_g.nc",  # Specific grid for 05m test
         "@N00W030.earth_faa_01m_p.nc",  # Specific grid for 01m test
         # Earth vertical gravity gradient grids
         "@earth_vgg_01d_g",
diff --git a/pygmt/tests/test_datasets_earth_age.py b/pygmt/tests/test_datasets_earth_age.py
index 182425e860a..16b7784e4f6 100644
--- a/pygmt/tests/test_datasets_earth_age.py
+++ b/pygmt/tests/test_datasets_earth_age.py
@@ -59,7 +59,6 @@ def test_earth_age_01d_with_region():
     npt.assert_allclose(data.max(), 125.1189)
 
 
-
 def test_earth_age_05m_without_region():
     """
     Test loading high-resolution earth age without passing 'region'.
diff --git a/pygmt/tests/test_datasets_earth_free_air_anomaly.py b/pygmt/tests/test_datasets_earth_free_air_anomaly.py
index 8c26bae533f..c9f3a782f19 100644
--- a/pygmt/tests/test_datasets_earth_free_air_anomaly.py
+++ b/pygmt/tests/test_datasets_earth_free_air_anomaly.py
@@ -57,22 +57,6 @@ def test_earth_faa_01d_with_region():
     npt.assert_allclose(data.max(), 69.524994)
 
 
-def test_earth_faa_05m_with_region():
-    """
-    Test loading a subregion of high-resolution earth free air anomaly data.
-    """
-    data = load_earth_free_air_anomaly(
-        resolution="05m", region=[-115, -112, 4, 6], registration="gridline"
-    )
-    assert data.shape == (25, 37)
-    assert data.lat.min() == 4
-    assert data.lat.max() == 6
-    assert data.lon.min() == -115
-    assert data.lon.max() == -112
-    npt.assert_allclose(data.min(), -20.5)
-    npt.assert_allclose(data.max(), -3.9500122)
-
-
 def test_earth_faa_05m_without_region():
     """
     Test loading high-resolution earth free air anomaly without passing

From f66894758b093e503b9cd84aa0d3d3f8ccfd3252 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 10:11:00 -0500
Subject: [PATCH 23/40] remove test_earth_geoid_05m_with_region from
 test_datasets_earth_geoid.py

---
 pygmt/helpers/testing.py                 |  1 -
 pygmt/tests/test_datasets_earth_geoid.py | 17 -----------------
 2 files changed, 18 deletions(-)

diff --git a/pygmt/helpers/testing.py b/pygmt/helpers/testing.py
index 95512ec1dcb..6b6a4711757 100644
--- a/pygmt/helpers/testing.py
+++ b/pygmt/helpers/testing.py
@@ -184,7 +184,6 @@ def download_test_data():
         "@N00W030.earth_age_01m_g.nc",  # Specific grid for 01m test
         # Earth geoid grids
         "@earth_geoid_01d_g",
-        "@S90W180.earth_geoid_05m_g.nc",  # Specific grid for 05m test
         "@N00W030.earth_geoid_01m_g.nc",  # Specific grid for 01m test
         # Earth magnetic anomaly grids
         "@earth_mag_01d_g",
diff --git a/pygmt/tests/test_datasets_earth_geoid.py b/pygmt/tests/test_datasets_earth_geoid.py
index 2d76fa67d9a..f530987082d 100644
--- a/pygmt/tests/test_datasets_earth_geoid.py
+++ b/pygmt/tests/test_datasets_earth_geoid.py
@@ -57,23 +57,6 @@ def test_earth_geoid_01d_with_region():
     npt.assert_allclose(data.max(), 29.89)
 
 
-def test_earth_geoid_05m_with_region():
-    """
-    Test loading a subregion of high-resolution earth geoid.
-    """
-    data = load_earth_geoid(
-        resolution="05m", region=[-50, -40, 20, 30], registration="gridline"
-    )
-    assert data.coords["lat"].data.min() == 20.0
-    assert data.coords["lat"].data.max() == 30.0
-    assert data.coords["lon"].data.min() == -50.0
-    assert data.coords["lon"].data.max() == -40.0
-    npt.assert_allclose(data.min(), -32.79)
-    npt.assert_allclose(data.max(), 16.57)
-    assert data.sizes["lat"] == 121
-    assert data.sizes["lon"] == 121
-
-
 def test_earth_geoid_05m_without_region():
     """
     Test loading high-resolution earth geoid without passing 'region'.

From 78fc8c1c1b34ceb91492b3486de90e490e24681f Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 10:11:58 -0500
Subject: [PATCH 24/40] remove test_earth_mag_05m_with_region from
 test_datasets_earth_magnetic_anomaly.py

---
 pygmt/helpers/testing.py                         |  1 -
 .../test_datasets_earth_magnetic_anomaly.py      | 16 ----------------
 2 files changed, 17 deletions(-)

diff --git a/pygmt/helpers/testing.py b/pygmt/helpers/testing.py
index 6b6a4711757..c8fadf8fdb9 100644
--- a/pygmt/helpers/testing.py
+++ b/pygmt/helpers/testing.py
@@ -187,7 +187,6 @@ def download_test_data():
         "@N00W030.earth_geoid_01m_g.nc",  # Specific grid for 01m test
         # Earth magnetic anomaly grids
         "@earth_mag_01d_g",
-        "@S90W180.earth_mag_05m_g.nc",  # Specific grid for 05m test
         "@S30W060.earth_mag_02m_p.nc",  # Specific grid for 02m test
         "@earth_mag4km_01d_g",
         "@S90W180.earth_mag4km_05m_g.nc",  # Specific grid for 05m test
diff --git a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
index 00b2b896eb5..7603eba3ce4 100644
--- a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
+++ b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
@@ -57,22 +57,6 @@ def test_earth_mag_01d_with_region():
     npt.assert_allclose(data.max(), 127.39996)
 
 
-def test_earth_mag_05m_with_region():
-    """
-    Test loading a subregion of high-resolution earth magnetic anomaly data.
-    """
-    data = load_earth_magnetic_anomaly(
-        resolution="05m", region=[-115, -112, 4, 6], registration="gridline"
-    )
-    assert data.shape == (25, 37)
-    assert data.lat.min() == 4
-    assert data.lat.max() == 6
-    assert data.lon.min() == -115
-    assert data.lon.max() == -112
-    npt.assert_allclose(data.min(), -189.20001)
-    npt.assert_allclose(data.max(), 107)
-
-
 def test_earth_mag_05m_without_region():
     """
     Test loading high-resolution earth magnetic anomaly without passing

From ae6176d07f3fd3132631da4d91e0ed8ed85656d7 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 10:12:41 -0500
Subject: [PATCH 25/40] remove
 test_earth_vertical_gravity_gradient_05m_with_region from
 test_datasets_earth_vertical_gravity_gradient.py

---
 pygmt/helpers/testing.py                        |  1 -
 ..._datasets_earth_vertical_gravity_gradient.py | 17 -----------------
 2 files changed, 18 deletions(-)

diff --git a/pygmt/helpers/testing.py b/pygmt/helpers/testing.py
index c8fadf8fdb9..3c078f36a35 100644
--- a/pygmt/helpers/testing.py
+++ b/pygmt/helpers/testing.py
@@ -195,7 +195,6 @@ def download_test_data():
         "@N00W030.earth_faa_01m_p.nc",  # Specific grid for 01m test
         # Earth vertical gravity gradient grids
         "@earth_vgg_01d_g",
-        "@S90W180.earth_vgg_05m_g.nc",  # Specific grid for 05m test
         "@N00W030.earth_vgg_01m_p.nc",  # Specific grid for 01m test
         # Other cache files
         "@capitals.gmt",
diff --git a/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py b/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py
index 2030b909803..ee2864e2857 100644
--- a/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py
+++ b/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py
@@ -62,23 +62,6 @@ def test_earth_vertical_gravity_gradient_01d_with_region():
     npt.assert_allclose(data.max(), 19.78125)
 
 
-def test_earth_vertical_gravity_gradient_05m_with_region():
-    """
-    Test loading a subregion of high-resolution earth vgg.
-    """
-    data = load_earth_vertical_gravity_gradient(
-        resolution="05m", region=[-50, -40, 20, 26], registration="gridline"
-    )
-    assert data.coords["lat"].data.min() == 20.0
-    assert data.coords["lat"].data.max() == 26.0
-    assert data.coords["lon"].data.min() == -50.0
-    assert data.coords["lon"].data.max() == -40.0
-    npt.assert_allclose(data.min(), -107.625)
-    npt.assert_allclose(data.max(), 159.75)
-    assert data.sizes["lat"] == 73
-    assert data.sizes["lon"] == 121
-
-
 def test_earth_vertical_gravity_gradient_05m_without_region():
     """
     Test loading high-resolution earth vgg without passing 'region'.

From 3714cccfd7d3db0a549dcddf8890b6dc1b71e7d5 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 10:14:30 -0500
Subject: [PATCH 26/40] remove test_earth_relief_05m_with_region from
 test_datasets_earth_relief.py

---
 pygmt/tests/test_datasets_earth_relief.py | 17 -----------------
 1 file changed, 17 deletions(-)

diff --git a/pygmt/tests/test_datasets_earth_relief.py b/pygmt/tests/test_datasets_earth_relief.py
index e54c32f7321..1d4d06ef44b 100644
--- a/pygmt/tests/test_datasets_earth_relief.py
+++ b/pygmt/tests/test_datasets_earth_relief.py
@@ -103,23 +103,6 @@ def test_earth_relief_30m():
     npt.assert_allclose(data.max(), 5887.5)
 
 
-def test_earth_relief_05m_with_region():
-    """
-    Test loading a subregion of high-resolution earth relief grid.
-    """
-    data = load_earth_relief(
-        resolution="05m", region=[120, 160, 30, 60], registration="gridline"
-    )
-    assert data.coords["lat"].data.min() == 30.0
-    assert data.coords["lat"].data.max() == 60.0
-    assert data.coords["lon"].data.min() == 120.0
-    assert data.coords["lon"].data.max() == 160.0
-    assert data.data.min() == -9633.0
-    assert data.data.max() == 2532.0
-    assert data.sizes["lat"] == 361
-    assert data.sizes["lon"] == 481
-
-
 def test_earth_gebcosi_15m_with_region():
     """
     Test loading a subregion of 15 arc-minutes resolution earth_gebcosi grid.

From 9bfb3178d70dbcd8a8c9a7b57aec3b7ee93d5dff Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 15:09:08 -0500
Subject: [PATCH 27/40] uncomment pull_request for cache data

---
 .github/workflows/cache_data.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/cache_data.yaml b/.github/workflows/cache_data.yaml
index 0c3f748a162..ef2704fb67c 100644
--- a/.github/workflows/cache_data.yaml
+++ b/.github/workflows/cache_data.yaml
@@ -3,7 +3,7 @@ name: Cache data
 
 on:
   # Uncomment the 'pull_request' line below to manually re-cache data artifacts
-  # pull_request:
+  pull_request:
   # Schedule runs on 12 noon every Sunday
   schedule:
     - cron: '0 12 * * 0'

From bea25d5ce2d7661e18b89c4bd404143585d1335c Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Tue, 27 Dec 2022 16:22:38 -0500
Subject: [PATCH 28/40] recomment pull_request for cache data

---
 .github/workflows/cache_data.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/cache_data.yaml b/.github/workflows/cache_data.yaml
index ef2704fb67c..0c3f748a162 100644
--- a/.github/workflows/cache_data.yaml
+++ b/.github/workflows/cache_data.yaml
@@ -3,7 +3,7 @@ name: Cache data
 
 on:
   # Uncomment the 'pull_request' line below to manually re-cache data artifacts
-  pull_request:
+  # pull_request:
   # Schedule runs on 12 noon every Sunday
   schedule:
     - cron: '0 12 * * 0'

From 05f79a191dc4333315bfa290c04378573f122792 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Wed, 28 Dec 2022 09:18:17 -0500
Subject: [PATCH 29/40] Apply suggestions from code review

Co-authored-by: Wei Ji <23487320+weiji14@users.noreply.github.com>
---
 pygmt/datasets/earth_age.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/pygmt/datasets/earth_age.py b/pygmt/datasets/earth_age.py
index 43cee8341d7..a84fc93c733 100644
--- a/pygmt/datasets/earth_age.py
+++ b/pygmt/datasets/earth_age.py
@@ -44,8 +44,7 @@ def load_earth_age(resolution="01d", region=None, registration=None):
 
     registration : str
         Grid registration type. Either ``"pixel"`` for pixel registration or
-        ``"gridline"`` for gridline registration. Default is ``"gridline"``
-        when available.
+        ``"gridline"`` for gridline registration. Default is ``"gridline"``.
 
     Returns
     -------

From 8b09c33051eab9bae087226b5750b22de7711457 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Wed, 28 Dec 2022 09:18:53 -0500
Subject: [PATCH 30/40] Apply suggestions from code review

Co-authored-by: Wei Ji <23487320+weiji14@users.noreply.github.com>
---
 pygmt/datasets/earth_free_air_anomaly.py          | 2 +-
 pygmt/datasets/earth_geoid.py                     | 3 +--
 pygmt/datasets/earth_magnetic_anomaly.py          | 2 +-
 pygmt/datasets/earth_relief.py                    | 2 +-
 pygmt/datasets/earth_vertical_gravity_gradient.py | 3 +--
 5 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/pygmt/datasets/earth_free_air_anomaly.py b/pygmt/datasets/earth_free_air_anomaly.py
index d35497b3306..a81b7e77895 100644
--- a/pygmt/datasets/earth_free_air_anomaly.py
+++ b/pygmt/datasets/earth_free_air_anomaly.py
@@ -45,7 +45,7 @@ def load_earth_free_air_anomaly(resolution="01d", region=None, registration=None
     registration : str
         Grid registration type. Either ``"pixel"`` for pixel registration or
         ``"gridline"`` for gridline registration. Default is ``"gridline"``
-        when available.
+        for all resolutions except ``"01m"`` which is ``"pixel"`` only.
 
     Returns
     -------
diff --git a/pygmt/datasets/earth_geoid.py b/pygmt/datasets/earth_geoid.py
index 5025e7383fe..fa5d1ad020d 100644
--- a/pygmt/datasets/earth_geoid.py
+++ b/pygmt/datasets/earth_geoid.py
@@ -44,8 +44,7 @@ def load_earth_geoid(resolution="01d", region=None, registration=None):
 
     registration : str
         Grid registration type. Either ``"pixel"`` for pixel registration or
-        ``"gridline"`` for gridline registration. Default is ``"gridline"``
-        when available.
+        ``"gridline"`` for gridline registration. Default is ``"gridline"``.
 
     Returns
     -------
diff --git a/pygmt/datasets/earth_magnetic_anomaly.py b/pygmt/datasets/earth_magnetic_anomaly.py
index 629c5ba974e..0de1d9e52c6 100644
--- a/pygmt/datasets/earth_magnetic_anomaly.py
+++ b/pygmt/datasets/earth_magnetic_anomaly.py
@@ -50,7 +50,7 @@ def load_earth_magnetic_anomaly(
     registration : str
         Grid registration type. Either ``"pixel"`` for pixel registration or
         ``"gridline"`` for gridline registration. Default is ``"gridline"``
-        when available.
+        for all resolutions except ``"02m"`` which is ``"pixel"`` only.
 
     mag4km : bool
         Choose the data version to use. The default is ``False``, which is
diff --git a/pygmt/datasets/earth_relief.py b/pygmt/datasets/earth_relief.py
index 7a2ea6c3115..af12d59a301 100644
--- a/pygmt/datasets/earth_relief.py
+++ b/pygmt/datasets/earth_relief.py
@@ -58,7 +58,7 @@ def load_earth_relief(
     registration : str
         Grid registration type. Either ``"pixel"`` for pixel registration or
         ``"gridline"`` for gridline registration. Default is ``"gridline"``
-        when available.
+        for all resolutions except ``"15s"`` which is ``"pixel"`` only.
 
     data_source : str
         Select the source for the Earth relief data.
diff --git a/pygmt/datasets/earth_vertical_gravity_gradient.py b/pygmt/datasets/earth_vertical_gravity_gradient.py
index 62b9dd2c802..fde1e82ccaa 100644
--- a/pygmt/datasets/earth_vertical_gravity_gradient.py
+++ b/pygmt/datasets/earth_vertical_gravity_gradient.py
@@ -46,8 +46,7 @@ def load_earth_vertical_gravity_gradient(
     registration : str
         Grid registration type. Either ``"pixel"`` for pixel registration or
         ``"gridline"`` for gridline registration. Default is ``"gridline"``
-        when available.
-
+        for all resolutions except ``"01m"`` which is ``"pixel"`` only.
 
     Returns
     -------

From 60c1eee8a9a47c83bab600b6b905b198e657bcc3 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Wed, 28 Dec 2022 09:20:53 -0500
Subject: [PATCH 31/40] remove 05m mag4km test

---
 pygmt/helpers/testing.py                      |  1 -
 .../test_datasets_earth_magnetic_anomaly.py   | 19 -------------------
 2 files changed, 20 deletions(-)

diff --git a/pygmt/helpers/testing.py b/pygmt/helpers/testing.py
index 3c078f36a35..01395c86093 100644
--- a/pygmt/helpers/testing.py
+++ b/pygmt/helpers/testing.py
@@ -189,7 +189,6 @@ def download_test_data():
         "@earth_mag_01d_g",
         "@S30W060.earth_mag_02m_p.nc",  # Specific grid for 02m test
         "@earth_mag4km_01d_g",
-        "@S90W180.earth_mag4km_05m_g.nc",  # Specific grid for 05m test
         # Earth free-air anomaly grids
         "@earth_faa_01d_g",
         "@N00W030.earth_faa_01m_p.nc",  # Specific grid for 01m test
diff --git a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
index 7603eba3ce4..fc01cbace7d 100644
--- a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
+++ b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
@@ -112,25 +112,6 @@ def test_earth_mag4km_01d_with_region():
     npt.assert_allclose(data.max(), 113.59985)
 
 
-def test_earth_mag4km_05m_with_region():
-    """
-    Test loading a subregion of high-resolution earth magnetic anomaly 4km
-    data.
-    """
-    data = load_earth_magnetic_anomaly(
-        resolution="05m",
-        region=[-115, -112, 4, 6],
-        registration="gridline",
-        mag4km=True,
-    )
-    assert data.shape == (25, 37)
-    assert data.lat.min() == 4
-    assert data.lat.max() == 6
-    assert data.lon.min() == -115
-    assert data.lon.max() == -112
-    npt.assert_allclose(data.min(), -128.40015)
-    npt.assert_allclose(data.max(), 76.80005)
-
 
 def test_earth_mag_02m_default_registration():
     """

From 224bbcfb6884eeafadfcd117d88bb2a780f11b69 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Wed, 28 Dec 2022 09:21:40 -0500
Subject: [PATCH 32/40] change 05m to 01m resolution in
 test_datasets_earth_magnetic_anomaly.py

---
 pygmt/tests/test_datasets_earth_magnetic_anomaly.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
index fc01cbace7d..e17feb003a5 100644
--- a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
+++ b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
@@ -57,13 +57,13 @@ def test_earth_mag_01d_with_region():
     npt.assert_allclose(data.max(), 127.39996)
 
 
-def test_earth_mag_05m_without_region():
+def test_earth_mag_01m_without_region():
     """
     Test loading high-resolution earth magnetic anomaly without passing
     'region'.
     """
     with pytest.raises(GMTInvalidInput):
-        load_earth_magnetic_anomaly("05m")
+        load_earth_magnetic_anomaly("01m")
 
 
 def test_earth_mag_incorrect_resolution_registration():

From c624d437836083ee0861aaa08a8f7f4194dd8eb1 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Wed, 28 Dec 2022 09:22:26 -0500
Subject: [PATCH 33/40] change 05m to 01m resolution in
 test_datasets_earth_age.py

---
 pygmt/tests/test_datasets_earth_age.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pygmt/tests/test_datasets_earth_age.py b/pygmt/tests/test_datasets_earth_age.py
index 16b7784e4f6..930888b025c 100644
--- a/pygmt/tests/test_datasets_earth_age.py
+++ b/pygmt/tests/test_datasets_earth_age.py
@@ -59,12 +59,12 @@ def test_earth_age_01d_with_region():
     npt.assert_allclose(data.max(), 125.1189)
 
 
-def test_earth_age_05m_without_region():
+def test_earth_age_01m_without_region():
     """
     Test loading high-resolution earth age without passing 'region'.
     """
     with pytest.raises(GMTInvalidInput):
-        load_earth_age("05m")
+        load_earth_age("01m")
 
 
 def test_earth_age_incorrect_resolution_registration():

From cad77964c86d90e5d9aa789138453a53fd5023f6 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Wed, 28 Dec 2022 09:23:36 -0500
Subject: [PATCH 34/40] change 05m to 01m resolution in
 test_datasets_earth_free_air_anomaly.py

---
 pygmt/tests/test_datasets_earth_free_air_anomaly.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pygmt/tests/test_datasets_earth_free_air_anomaly.py b/pygmt/tests/test_datasets_earth_free_air_anomaly.py
index c9f3a782f19..ea65a0e83a8 100644
--- a/pygmt/tests/test_datasets_earth_free_air_anomaly.py
+++ b/pygmt/tests/test_datasets_earth_free_air_anomaly.py
@@ -57,13 +57,13 @@ def test_earth_faa_01d_with_region():
     npt.assert_allclose(data.max(), 69.524994)
 
 
-def test_earth_faa_05m_without_region():
+def test_earth_faa_01m_without_region():
     """
     Test loading high-resolution earth free air anomaly without passing
     'region'.
     """
     with pytest.raises(GMTInvalidInput):
-        load_earth_free_air_anomaly("05m")
+        load_earth_free_air_anomaly("01m")
 
 
 def test_earth_faa_01m_default_registration():

From 706c5bcd5bb3096af4ad07741dd1e4213a05d90f Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Wed, 28 Dec 2022 09:24:54 -0500
Subject: [PATCH 35/40] change 05m to 01m resolution in
 test_datasets_earth_geoid.py

---
 pygmt/tests/test_datasets_earth_geoid.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pygmt/tests/test_datasets_earth_geoid.py b/pygmt/tests/test_datasets_earth_geoid.py
index f530987082d..639178c0ddc 100644
--- a/pygmt/tests/test_datasets_earth_geoid.py
+++ b/pygmt/tests/test_datasets_earth_geoid.py
@@ -57,12 +57,12 @@ def test_earth_geoid_01d_with_region():
     npt.assert_allclose(data.max(), 29.89)
 
 
-def test_earth_geoid_05m_without_region():
+def test_earth_geoid_01m_without_region():
     """
     Test loading high-resolution earth geoid without passing 'region'.
     """
     with pytest.raises(GMTInvalidInput):
-        load_earth_geoid("05m")
+        load_earth_geoid("01m")
 
 
 def test_earth_geoid_incorrect_resolution_registration():

From 9cb34ecfb815c856e5daa2a741ba6f4e406dce69 Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Wed, 28 Dec 2022 09:25:37 -0500
Subject: [PATCH 36/40] change 05m to 01m resolution in
 test_datasets_earth_relief.py

---
 pygmt/tests/test_datasets_earth_relief.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pygmt/tests/test_datasets_earth_relief.py b/pygmt/tests/test_datasets_earth_relief.py
index 1d4d06ef44b..22baff35fbf 100644
--- a/pygmt/tests/test_datasets_earth_relief.py
+++ b/pygmt/tests/test_datasets_earth_relief.py
@@ -136,12 +136,12 @@ def test_earth_relief_30s_synbath():
     npt.assert_allclose(data.max(), -2154)
 
 
-def test_earth_relief_05m_without_region():
+def test_earth_relief_01m_without_region():
     """
     Test loading high-resolution earth relief without passing 'region'.
     """
     with pytest.raises(GMTInvalidInput):
-        load_earth_relief("05m")
+        load_earth_relief("01m")
 
 
 def test_earth_relief_03s_landonly_srtm():

From 6235babe80928120c1d639022ec6b0b715b98e0d Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Wed, 28 Dec 2022 09:25:55 -0500
Subject: [PATCH 37/40] change 05m to 01m resolution in
 test_datasets_earth_vertical_gravity_gradient.py

---
 pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py b/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py
index ee2864e2857..44ef9f71885 100644
--- a/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py
+++ b/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py
@@ -62,12 +62,12 @@ def test_earth_vertical_gravity_gradient_01d_with_region():
     npt.assert_allclose(data.max(), 19.78125)
 
 
-def test_earth_vertical_gravity_gradient_05m_without_region():
+def test_earth_vertical_gravity_gradient_01m_without_region():
     """
     Test loading high-resolution earth vgg without passing 'region'.
     """
     with pytest.raises(GMTInvalidInput):
-        load_earth_vertical_gravity_gradient("05m")
+        load_earth_vertical_gravity_gradient("01m")
 
 
 def test_earth_vertical_gravity_gradient_incorrect_resolution_registration():

From f8553d57ceb5a50ba85f0f6b763d3e61022e47ec Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Wed, 28 Dec 2022 09:42:51 -0500
Subject: [PATCH 38/40] Apply suggestions from code review

Co-authored-by: Dongdong Tian <seisman.info@gmail.com>
---
 pygmt/tests/test_datasets_earth_magnetic_anomaly.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
index e17feb003a5..c1bffddab5e 100644
--- a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
+++ b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
@@ -57,13 +57,13 @@ def test_earth_mag_01d_with_region():
     npt.assert_allclose(data.max(), 127.39996)
 
 
-def test_earth_mag_01m_without_region():
+def test_earth_mag_02m_without_region():
     """
     Test loading high-resolution earth magnetic anomaly without passing
     'region'.
     """
     with pytest.raises(GMTInvalidInput):
-        load_earth_magnetic_anomaly("01m")
+        load_earth_magnetic_anomaly("02m")
 
 
 def test_earth_mag_incorrect_resolution_registration():

From a2e508d1762fac88b7dddf33acdb7c97d98895ca Mon Sep 17 00:00:00 2001
From: Will Schlitzer <schlitzer90@gmail.com>
Date: Wed, 28 Dec 2022 09:46:04 -0500
Subject: [PATCH 39/40] run make format

---
 pygmt/tests/test_datasets_earth_magnetic_anomaly.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
index c1bffddab5e..d93ba82c0f1 100644
--- a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
+++ b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
@@ -112,7 +112,6 @@ def test_earth_mag4km_01d_with_region():
     npt.assert_allclose(data.max(), 113.59985)
 
 
-
 def test_earth_mag_02m_default_registration():
     """
     Test that the grid returned by default for the 2 arc-minute resolution has

From cedfa26efebc8792c488f81883f62bcc9741e4ce Mon Sep 17 00:00:00 2001
From: Dongdong Tian <seisman.info@gmail.com>
Date: Wed, 28 Dec 2022 22:55:44 +0800
Subject: [PATCH 40/40] Always check if gridline is the default registration
 for 01d resolution

---
 pygmt/tests/test_datasets_earth_age.py              |  4 +---
 pygmt/tests/test_datasets_earth_free_air_anomaly.py |  8 ++++----
 pygmt/tests/test_datasets_earth_geoid.py            |  8 ++++----
 pygmt/tests/test_datasets_earth_magnetic_anomaly.py | 13 ++++++-------
 pygmt/tests/test_datasets_earth_relief.py           | 12 ++++++------
 ...test_datasets_earth_vertical_gravity_gradient.py |  8 ++++----
 6 files changed, 25 insertions(+), 28 deletions(-)

diff --git a/pygmt/tests/test_datasets_earth_age.py b/pygmt/tests/test_datasets_earth_age.py
index 930888b025c..b14c74352ca 100644
--- a/pygmt/tests/test_datasets_earth_age.py
+++ b/pygmt/tests/test_datasets_earth_age.py
@@ -48,9 +48,7 @@ def test_earth_age_01d_with_region():
     """
     Test loading low-resolution earth age with 'region'.
     """
-    data = load_earth_age(
-        resolution="01d", region=[-10, 10, -5, 5], registration="gridline"
-    )
+    data = load_earth_age(resolution="01d", region=[-10, 10, -5, 5])
     assert data.shape == (11, 21)
     assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-5, 6, 1))
diff --git a/pygmt/tests/test_datasets_earth_free_air_anomaly.py b/pygmt/tests/test_datasets_earth_free_air_anomaly.py
index ea65a0e83a8..f9164ac2e50 100644
--- a/pygmt/tests/test_datasets_earth_free_air_anomaly.py
+++ b/pygmt/tests/test_datasets_earth_free_air_anomaly.py
@@ -31,12 +31,13 @@ def test_earth_faa_01d():
     """
     Test some properties of the free air anomaly 01d data.
     """
-    data = load_earth_free_air_anomaly(resolution="01d", registration="gridline")
+    data = load_earth_free_air_anomaly(resolution="01d")
     assert data.name == "free_air_anomaly"
     assert data.attrs["long_name"] == "IGPP Global Earth Free-Air Anomaly"
     assert data.attrs["units"] == "mGal"
     assert data.attrs["horizontal_datum"] == "WGS84"
     assert data.shape == (181, 361)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-90, 91, 1))
     npt.assert_allclose(data.lon, np.arange(-180, 181, 1))
     npt.assert_allclose(data.min(), -275.75)
@@ -47,10 +48,9 @@ def test_earth_faa_01d_with_region():
     """
     Test loading low-resolution earth free air anomaly with 'region'.
     """
-    data = load_earth_free_air_anomaly(
-        resolution="01d", region=[-10, 10, -5, 5], registration="gridline"
-    )
+    data = load_earth_free_air_anomaly(resolution="01d", region=[-10, 10, -5, 5])
     assert data.shape == (11, 21)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-5, 6, 1))
     npt.assert_allclose(data.lon, np.arange(-10, 11, 1))
     npt.assert_allclose(data.min(), -58.75)
diff --git a/pygmt/tests/test_datasets_earth_geoid.py b/pygmt/tests/test_datasets_earth_geoid.py
index 639178c0ddc..2fdfcee2057 100644
--- a/pygmt/tests/test_datasets_earth_geoid.py
+++ b/pygmt/tests/test_datasets_earth_geoid.py
@@ -31,12 +31,13 @@ def test_earth_geoid_01d():
     """
     Test some properties of the earth geoid 01d data.
     """
-    data = load_earth_geoid(resolution="01d", registration="gridline")
+    data = load_earth_geoid(resolution="01d")
     assert data.name == "earth_geoid"
     assert data.attrs["units"] == "m"
     assert data.attrs["long_name"] == "EGM2008 Global Earth Geoid"
     assert data.attrs["horizontal_datum"] == "WGS84"
     assert data.shape == (181, 361)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-90, 91, 1))
     npt.assert_allclose(data.lon, np.arange(-180, 181, 1))
     npt.assert_allclose(data.min(), -106.45)
@@ -47,10 +48,9 @@ def test_earth_geoid_01d_with_region():
     """
     Test loading low-resolution earth geoid with 'region'.
     """
-    data = load_earth_geoid(
-        resolution="01d", region=[-10, 10, -5, 5], registration="gridline"
-    )
+    data = load_earth_geoid(resolution="01d", region=[-10, 10, -5, 5])
     assert data.shape == (11, 21)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-5, 6, 1))
     npt.assert_allclose(data.lon, np.arange(-10, 11, 1))
     npt.assert_allclose(data.min(), 4.87)
diff --git a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
index d93ba82c0f1..3ba87eaa209 100644
--- a/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
+++ b/pygmt/tests/test_datasets_earth_magnetic_anomaly.py
@@ -31,12 +31,13 @@ def test_earth_mag_01d():
     """
     Test some properties of the magnetic anomaly 01d data.
     """
-    data = load_earth_magnetic_anomaly(resolution="01d", registration="gridline")
+    data = load_earth_magnetic_anomaly(resolution="01d")
     assert data.name == "magnetic_anomaly"
     assert data.attrs["long_name"] == "Earth magnetic anomaly"
     assert data.attrs["units"] == "nT"
     assert data.attrs["horizontal_datum"] == "WGS84"
     assert data.shape == (181, 361)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-90, 91, 1))
     npt.assert_allclose(data.lon, np.arange(-180, 181, 1))
     npt.assert_allclose(data.min(), -384)
@@ -47,10 +48,9 @@ def test_earth_mag_01d_with_region():
     """
     Test loading low-resolution earth magnetic anomaly with 'region'.
     """
-    data = load_earth_magnetic_anomaly(
-        resolution="01d", region=[-10, 10, -5, 5], registration="gridline"
-    )
+    data = load_earth_magnetic_anomaly(resolution="01d", region=[-10, 10, -5, 5])
     assert data.shape == (11, 21)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-5, 6, 1))
     npt.assert_allclose(data.lon, np.arange(-10, 11, 1))
     npt.assert_allclose(data.min(), -180.40002)
@@ -81,14 +81,13 @@ def test_earth_mag4km_01d():
     """
     Test some properties of the magnetic anomaly 4km 01d data.
     """
-    data = load_earth_magnetic_anomaly(
-        resolution="01d", registration="gridline", mag4km=True
-    )
+    data = load_earth_magnetic_anomaly(resolution="01d", mag4km=True)
     assert data.name == "magnetic_anomaly"
     assert data.attrs["long_name"] == "Earth magnetic anomaly"
     assert data.attrs["units"] == "nT"
     assert data.attrs["horizontal_datum"] == "WGS84"
     assert data.shape == (181, 361)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-90, 91, 1))
     npt.assert_allclose(data.lon, np.arange(-180, 181, 1))
     npt.assert_allclose(data.min(), -799.19995)
diff --git a/pygmt/tests/test_datasets_earth_relief.py b/pygmt/tests/test_datasets_earth_relief.py
index 22baff35fbf..e8b176f491b 100644
--- a/pygmt/tests/test_datasets_earth_relief.py
+++ b/pygmt/tests/test_datasets_earth_relief.py
@@ -47,10 +47,9 @@ def test_earth_relief_01d_gebco(data_source):
     Test some properties of the earth relief 01d data with GEBCO and GEBOCSI
     data.
     """
-    data = load_earth_relief(
-        resolution="01d", registration="gridline", data_source=data_source
-    )
+    data = load_earth_relief(resolution="01d", data_source=data_source)
     assert data.shape == (181, 361)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-90, 91, 1))
     npt.assert_allclose(data.lon, np.arange(-180, 181, 1))
     npt.assert_allclose(data.min(), -8598)
@@ -64,10 +63,10 @@ def test_earth_relief_01d_with_region_srtm():
     data = load_earth_relief(
         resolution="01d",
         region=[-10, 10, -5, 5],
-        registration="gridline",
         data_source="igpp",
     )
     assert data.shape == (11, 21)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-5, 6, 1))
     npt.assert_allclose(data.lon, np.arange(-10, 11, 1))
     npt.assert_allclose(data.min(), -5154)
@@ -81,10 +80,10 @@ def test_earth_relief_01d_with_region_gebco():
     data = load_earth_relief(
         resolution="01d",
         region=[-10, 10, -5, 5],
-        registration="gridline",
         data_source="gebco",
     )
     assert data.shape == (11, 21)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-5, 6, 1))
     npt.assert_allclose(data.lon, np.arange(-10, 11, 1))
     npt.assert_allclose(data.min(), -5146)
@@ -95,8 +94,9 @@ def test_earth_relief_30m():
     """
     Test some properties of the earth relief 30m data.
     """
-    data = load_earth_relief(resolution="30m", registration="gridline")
+    data = load_earth_relief(resolution="30m")
     assert data.shape == (361, 721)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-90, 90.5, 0.5))
     npt.assert_allclose(data.lon, np.arange(-180, 180.5, 0.5))
     npt.assert_allclose(data.min(), -9454.5)
diff --git a/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py b/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py
index 44ef9f71885..e9307d3742d 100644
--- a/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py
+++ b/pygmt/tests/test_datasets_earth_vertical_gravity_gradient.py
@@ -33,14 +33,13 @@ def test_earth_vertical_gravity_gradient_01d():
     """
     Test some properties of the earth vgg 01d data.
     """
-    data = load_earth_vertical_gravity_gradient(
-        resolution="01d", registration="gridline"
-    )
+    data = load_earth_vertical_gravity_gradient(resolution="01d")
     assert data.name == "earth_vgg"
     assert data.attrs["units"] == "Eotvos"
     assert data.attrs["long_name"] == "IGPP Global Earth Vertical Gravity Gradient"
     assert data.attrs["horizontal_datum"] == "WGS84"
     assert data.shape == (181, 361)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-90, 91, 1))
     npt.assert_allclose(data.lon, np.arange(-180, 181, 1))
     npt.assert_allclose(data.min(), -136.34375)
@@ -53,9 +52,10 @@ def test_earth_vertical_gravity_gradient_01d_with_region():
     Test loading low-resolution earth vgg with 'region'.
     """
     data = load_earth_vertical_gravity_gradient(
-        resolution="01d", region=[-10, 10, -5, 5], registration="gridline"
+        resolution="01d", region=[-10, 10, -5, 5]
     )
     assert data.shape == (11, 21)
+    assert data.gmt.registration == 0
     npt.assert_allclose(data.lat, np.arange(-5, 6, 1))
     npt.assert_allclose(data.lon, np.arange(-10, 11, 1))
     npt.assert_allclose(data.min(), -16.34375)