🎨 Datashade points to grids with the correct aspect ratio

Putting the datashader functionality into the Region class, so that we can make use of the bounding box information! Takes in a pandas.DataFrame table of x, y, z points, and outputs an xarray.DataArray grid for visualization purposes at the pre-set scale. Do some simple algebra math to set the correct aspect ratio with only plot_width as input. Standardized on the variable names to be ds_* for xarray.Datasets and df_* for pandas.Dataframes. Storing all of the intermediate Zarr and Parquet data files into an ATLXI folder. Will update plots in another commit once I sort out some issues, and maybe start a new file called visualization.py to handle the plotting code.
weiji14 · Jun 2, 2020 · 1248f02 · 1248f02
1 parent 942968a
commit 1248f02
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diff --git a/atl11_play.ipynb b/atl11_play.ipynb
@@ -278,8 +278,9 @@
    "outputs": [],
    "source": [
     "# Do the actual computation to find data points within region of interest\n",
-    "region = regions[\"kamb\"]  # Select Kamb Ice Stream region\n",
-    "ds_subset = region.subset(ds=ds)\n",
+    "placename: str = \"kamb\"  # Select Kamb Ice Stream region\n",
+    "region: deepicedrain.Region = regions[placename]\n",
+    "ds_subset: xr.Dataset = region.subset(ds=ds)\n",
     "ds_subset = ds_subset.unify_chunks()\n",
     "ds_subset = ds_subset.compute()"
    ]
@@ -301,12 +302,12 @@
     }
    ],
    "source": [
-    "# Save to NetCDF/Zarr formats for distribution\n",
-    "ds_subset.to_netcdf(\n",
-    "    path=\"atl11_subset.nc\", engine=\"h5netcdf\",\n",
-    ")\n",
+    "# Save to Zarr/NetCDF formats for distribution\n",
     "ds_subset.to_zarr(\n",
-    "    store=\"atl11_subset.zarr\", mode=\"w\", consolidated=True,\n",
+    "    store=f\"ATLXI/ds_subset_{placename}.zarr\", mode=\"w\", consolidated=True,\n",
+    ")\n",
+    "ds_subset.to_netcdf(\n",
+    "    path=f\"ATLXI/ds_subset_{placename}.nc\", engine=\"h5netcdf\",\n",
     ")"
    ]
   },
@@ -599,7 +600,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "delta_h = dh.dropna(dim=\"ref_pt\").to_dataset(name=\"delta_height\")\n",
+    "delta_h: xr.Dataset = dh.dropna(dim=\"ref_pt\").to_dataset(name=\"delta_height\")\n",
     "delta_h"
    ]
   },
@@ -609,8 +610,8 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "dhdf = delta_h.to_dataframe()\n",
-    "dhdf.head()"
+    "df_dh: pd.DataFrame = delta_h.to_dataframe()\n",
+    "df_dh.head()"
    ]
   },
   {
@@ -619,9 +620,10 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "# dhdf.to_parquet(\"temp_dhdf.parquet\")\n",
-    "# dhdf = pd.read_parquet(\"temp_dhdf.parquet\")\n",
-    "# dhdf = dhdf.sample(n=1_000_000)"
+    "# Save or Load delta height data\n",
+    "# df_dh.to_parquet(f\"ATLXI/df_dh_{placename}.parquet\")\n",
+    "# df_dh: pd.DataFrame = pd.read_parquet(f\"ATLXI/df_dh_{placename}.parquet\")\n",
+    "# df_dh = df_dh.sample(n=1_000_000)"
    ]
   },
   {
@@ -681,15 +683,7 @@
    "outputs": [],
    "source": [
     "# Datashade our height values (vector points) onto a grid (raster image)\n",
-    "canvas = datashader.Canvas(\n",
-    "    plot_width=900,\n",
-    "    plot_height=900,\n",
-    "    x_range=(region.xmin, region.xmax),\n",
-    "    y_range=(region.ymin, region.ymax),\n",
-    ")\n",
-    "agg_grid = canvas.points(\n",
-    "    source=dhdf, x=\"x\", y=\"y\", agg=datashader.mean(column=\"delta_height\")\n",
-    ")\n",
+    "agg_grid: xr.DataArray = region.datashade(df=df_dh, z_dim=\"delta_height\")\n",
     "agg_grid"
    ]
   },
@@ -749,7 +743,7 @@
     "fig.colorbar(\n",
     "    position=\"JCR+e\", frame=[\"af\", 'x+l\"Elevation Change from Cycle 5 to 6\"', \"y+lm\"],\n",
     ")\n",
-    "fig.savefig(f\"figures/plot_atl11_{placename}.png\")\n",
+    "fig.savefig(f\"figures/plot_atl11_dh56_{placename}.png\")\n",
     "fig.show(width=600)"
    ]
   },
@@ -798,7 +792,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "dhdf.hvplot.points(\n",
+    "df_dh.hvplot.points(\n",
     "    # title=\"Elevation Change (metres) from Cycle 5 to 6\",\n",
     "    x=\"x\",\n",
     "    y=\"y\",\n",
@@ -824,7 +818,7 @@
    "outputs": [],
    "source": [
     "points = hv.Points(\n",
-    "    data=dhdf,\n",
+    "    data=df_dh,\n",
     "    kdims=[\"x\", \"y\"],\n",
     "    vdims=[\"delta_height\"],\n",
     "    # datatype=[\"xarray\"],\n",

diff --git a/atl11_play.py b/atl11_play.py
@@ -89,6 +89,7 @@
     longitude=ds.longitude, latitude=ds.latitude
 )
 
+
 # %%
 # Also set x, y as coordinates in xarray.Dataset
 ds = ds.set_coords(names=["x", "y"])
@@ -155,18 +156,19 @@
 
 # %%
 # Do the actual computation to find data points within region of interest
-region = regions["kamb"]  # Select Kamb Ice Stream region
-ds_subset = region.subset(ds=ds)
+placename: str = "kamb"  # Select Kamb Ice Stream region
+region: deepicedrain.Region = regions[placename]
+ds_subset: xr.Dataset = region.subset(ds=ds)
 ds_subset = ds_subset.unify_chunks()
 ds_subset = ds_subset.compute()
 
 # %%
-# Save to NetCDF/Zarr formats for distribution
-ds_subset.to_netcdf(
-    path="atl11_subset.nc", engine="h5netcdf",
-)
+# Save to Zarr/NetCDF formats for distribution
 ds_subset.to_zarr(
-    store="atl11_subset.zarr", mode="w", consolidated=True,
+    store=f"ATLXI/ds_subset_{placename}.zarr", mode="w", consolidated=True,
+)
+ds_subset.to_netcdf(
+    path=f"ATLXI/ds_subset_{placename}.nc", engine="h5netcdf",
 )
 
 # %%
@@ -279,17 +281,18 @@
 dh = dh.persist()
 
 # %%
-delta_h = dh.dropna(dim="ref_pt").to_dataset(name="delta_height")
+delta_h: xr.Dataset = dh.dropna(dim="ref_pt").to_dataset(name="delta_height")
 delta_h
 
 # %%
-dhdf = delta_h.to_dataframe()
-dhdf.head()
+df_dh: pd.DataFrame = delta_h.to_dataframe()
+df_dh.head()
 
 # %%
-# dhdf.to_parquet("temp_dhdf.parquet")
-# dhdf = pd.read_parquet("temp_dhdf.parquet")
-# dhdf = dhdf.sample(n=1_000_000)
+# Save or Load delta height data
+# df_dh.to_parquet(f"ATLXI/df_dh_{placename}.parquet")
+# df_dh: pd.DataFrame = pd.read_parquet(f"ATLXI/df_dh_{placename}.parquet")
+# df_dh = df_dh.sample(n=1_000_000)
 
 # %% [markdown]
 # ## Plot elevation difference for a region
@@ -326,15 +329,7 @@
 
 # %%
 # Datashade our height values (vector points) onto a grid (raster image)
-canvas = datashader.Canvas(
-    plot_width=900,
-    plot_height=900,
-    x_range=(region.xmin, region.xmax),
-    y_range=(region.ymin, region.ymax),
-)
-agg_grid = canvas.points(
-    source=dhdf, x="x", y="y", agg=datashader.mean(column="delta_height")
-)
+agg_grid: xr.DataArray = region.datashade(df=df_dh, z_dim="delta_height")
 agg_grid
 
 # %%
@@ -370,7 +365,7 @@
 fig.colorbar(
     position="JCR+e", frame=["af", 'x+l"Elevation Change from Cycle 5 to 6"', "y+lm"],
 )
-fig.savefig(f"figures/plot_atl11_{placename}.png")
+fig.savefig(f"figures/plot_atl11_dh56_{placename}.png")
 fig.show(width=600)
 
 
@@ -393,7 +388,7 @@
 spread_grid
 
 # %%
-dhdf.hvplot.points(
+df_dh.hvplot.points(
     # title="Elevation Change (metres) from Cycle 5 to 6",
     x="x",
     y="y",
@@ -413,7 +408,7 @@
 
 # %%
 points = hv.Points(
-    data=dhdf,
+    data=df_dh,
     kdims=["x", "y"],
     vdims=["delta_height"],
     # datatype=["xarray"],