radiantearth · cholmes · Jan 8, 2019 · Oct 4, 2018 · Dec 31, 2018 · Dec 31, 2018
diff --git a/extensions/README.md b/extensions/README.md
@@ -53,6 +53,7 @@ stable for over a year and are used in twenty or more implementations.
 | [Single Item](single-item/README.md) (`item`)                | Item             | Provides a way to specify several fields in individual Items that usually reside on the collection-level such as license and providers. | *Proposal* |
 | [Scientific](scientific//README.md) (`sci`)                  | Item             | Scientific metadata is considered to be data that indicate from which publication a collection originates and how the collection itself should be cited or referenced. | *Proposal* |
 | [Transaction](transaction//README.md)                        | API              | Provides an API extension to support the creation, editing, and deleting of items on a specific WFS3 collection. | *Pilot* |
+| [Point Cloud](pointcloud/README.md) (`pc`)             	| Item	| Provides a way to describe point cloud datasets. The point clouds can come from either active or passive sensors, and data is frequently acquired using tools such as LiDAR or coincidence-matched imagery. | *Proposal* |
 
 ## Third-party / vendor extensions
 

diff --git a/extensions/pointcloud/README.md b/extensions/pointcloud/README.md
@@ -0,0 +1,51 @@
+# Point Cloud Extension Specification (`pc`)
+
+**Extension [Maturity Classification](../README.md#extension-maturity): Proposal**
+
+This document explains the fields of the Point Cloud Extension to a STAC Item,
+which allows STAC to more fully describe point cloud datasets. The point clouds can
+come from either active or passive sensors, and data is frequently acquired using
+tools such as LiDAR or coincidence-matched imagery.
+
+- [Example](example-alaska.json)
+- JSON Schema is missing. PRs are welcome.
+
+## Item Fields
+
+| Field Name    | Type                | Description |
+| ------------- | ------------------- | ----------- |
+| pc:count      | integer             | The number of points in the item. |
+| pc:density    | number              | Number of points per square unit area. |
+| pc:encoding   | string              | Content encoding or format of the data. |
+| pc:schema     | [Schema Object]     | A sequential array of items that define the dimensions and their types. |
+| pc:statistics | [Statistics Object] | A sequential array of items mapping to `pc:schema` defines per-channel statistics. |
+| pc:type       | string              | Phenomenology type for the point cloud. Valid values include `lidar`, `eopc`, `radar`, `sonar`. |
+
+### Schema Object
+
+A sequential array of items that define the dimensions and their types.
+
+| Field Name | Type    | Description |
+| ---------- | ------- | -------------------------- |
+| name       | string  | The name of the dimension. |
+| size       | integer | |
+| type       | string  | |
+
+### Statistics Object
+
+A sequential array of items mapping to `pc:schema` defines per-channel statistics.
+
+| Field Name | Type    | Description |
+| ---------- | ------- | ----------- |
+| average    | number  | The average of the channel. |
+| count      | integer | The number of elements in the channel. |
+| maximum    | number  | The maximum value of the channel. |
+| minimum    | number  | The minimum value of the channel. |
+| name       | string  | The name of the channel. |
+| position   | integer | |
+| stddev     | number  | The standard deviation of the channel. |
+| variance   | number  | The variance of the channel. |
+
+## Implementations
+
+None yet, still in proposal stage.
diff --git a/extensions/pointcloud/example-alaska.json b/extensions/pointcloud/example-alaska.json
@@ -0,0 +1,261 @@
+{
+  "assets": {},
+  "bbox": {
+    "maxx": -149.2527639,
+    "maxy": 61.78936655,
+    "maxz": 1981.200833,
+    "minx": -149.3006585,
+    "miny": 61.76668361,
+    "minz": 11.48480563
+  },
+  "geometry": {
+    "coordinates": [
+      [
+        [
+          [
+            -149.30045496703195,
+            61.76682620765713
+          ],
+          [
+            -149.25327277445712,
+            61.76657763000873
+          ],
+          [
+            -149.25272374552367,
+            61.78921108684322
+          ],
+          [
+            -149.30023535632952,
+            61.7894132390075
+          ],
+          [
+            -149.30080489041393,
+            61.766924315502195
+          ],
+          [
+            -149.30045496703195,
+            61.76682620765713
+          ]
+        ]
+      ]
+    ],
+    "type": "MultiPolygon"
+  },
+  "id": "AK_MatanuskaSusitna-Lot2_2011_000227.laz",
+  "properties": {
+    "c:description": "USGS 3DEP LiDAR",
+    "c:id": "MODIFICATION                   ",
+    "datetime": "2013-05-14T00:00:00",
+    "license": "LICENSE",
+    "pc:avg_pt_per_sq_unit": 3.163692583,
+    "pc:count": 64473760,
+    "pc:density": 0.9482590115,
+    "pc:encoding": "LASzip",
+    "pc:schema": [
+      {
+        "name": "X",
+        "size": 8,
+        "type": "floating"
+      },
+      {
+        "name": "Y",
+        "size": 8,
+        "type": "floating"
+      },
+      {
+        "name": "Z",
+        "size": 8,
+        "type": "floating"
+      },
+      {
+        "name": "Intensity",
+        "size": 2,
+        "type": "unsigned"
+      },
+      {
+        "name": "ReturnNumber",
+        "size": 1,
+        "type": "unsigned"
+      },
+      {
+        "name": "NumberOfReturns",
+        "size": 1,
+        "type": "unsigned"
+      },
+      {
+        "name": "ScanDirectionFlag",
+        "size": 1,
+        "type": "unsigned"
+      },
+      {
+        "name": "EdgeOfFlightLine",
+        "size": 1,
+        "type": "unsigned"
+      },
+      {
+        "name": "Classification",
+        "size": 1,
+        "type": "unsigned"
+      },
+      {
+        "name": "ScanAngleRank",
+        "size": 4,
+        "type": "floating"
+      },
+      {
+        "name": "UserData",
+        "size": 1,
+        "type": "unsigned"
+      },
+      {
+        "name": "PointSourceId",
+        "size": 2,
+        "type": "unsigned"
+      },
+      {
+        "name": "GpsTime",
+        "size": 8,
+        "type": "floating"
+      }
+    ],
+    "pc:statistics": [
+      {
+        "average": 1765797.419,
+        "count": 64473760,
+        "maximum": 1769746,
+        "minimum": 1761544.01,
+        "name": "X",
+        "position": 0,
+        "stddev": 2340.346622,
+        "variance": 5477222.31
+      },
+      {
+        "average": 2842320.787,
+        "count": 64473760,
+        "maximum": 2846625,
+        "minimum": 2838423.01,
+        "name": "Y",
+        "position": 1,
+        "stddev": 2446.005498,
+        "variance": 5982942.898
+      },
+      {
+        "average": 3760.301515,
+        "count": 64473760,
+        "maximum": 6499.99,
+        "minimum": 37.68,
+        "name": "Z",
+        "position": 2,
+        "stddev": 953.5224496,
+        "variance": 909205.062
+      },
+      {
+        "average": 176.7857038,
+        "count": 64473760,
+        "maximum": 255,
+        "minimum": 0,
+        "name": "Intensity",
+        "position": 3,
+        "stddev": 92.00839536,
+        "variance": 8465.544817
+      },
+      {
+        "average": 1.214258343,
+        "count": 64473760,
+        "maximum": 5,
+        "minimum": 1,
+        "name": "ReturnNumber",
+        "position": 4,
+        "stddev": 0.7263398082,
+        "variance": 0.527569517
+      },
+      {
+        "average": 1.376616394,
+        "count": 64473760,
+        "maximum": 5,
+        "minimum": 1,
+        "name": "NumberOfReturns",
+        "position": 5,
+        "stddev": 1.070825579,
+        "variance": 1.146667421
+      },
+      {
+        "average": 0.5003097849,
+        "count": 64473760,
+        "maximum": 1,
+        "minimum": 0,
+        "name": "ScanDirectionFlag",
+        "position": 6,
+        "stddev": 0.4999999683,
+        "variance": 0.2499999683
+      },
+      {
+        "average": 0.000881211209,
+        "count": 64473760,
+        "maximum": 1,
+        "minimum": 0,
+        "name": "EdgeOfFlightLine",
+        "position": 7,
+        "stddev": 0.02967213003,
+        "variance": 0.0008804353008
+      },
+      {
+        "average": 17.21186159,
+        "count": 64473760,
+        "maximum": 129,
+        "minimum": 2,
+        "name": "Classification",
+        "position": 8,
+        "stddev": 31.34383656,
+        "variance": 982.4360901
+      },
+      {
+        "average": 0.3183486119,
+        "count": 64473760,
+        "maximum": 24,
+        "minimum": -22,
+        "name": "ScanAngleRank",
+        "position": 9,
+        "stddev": 9.934022398,
+        "variance": 98.684801
+      },
+      {
+        "average": 0,
+        "count": 64473760,
+        "maximum": 0,
+        "minimum": 0,
+        "name": "UserData",
+        "position": 10,
+        "stddev": 0,
+        "variance": 0
+      },
+      {
+        "average": 10733.9377,
+        "count": 64473760,
+        "maximum": 12042,
+        "minimum": 1084,
+        "name": "PointSourceId",
+        "position": 11,
+        "stddev": 3522.808499,
+        "variance": 12410179.72
+      },
+      {
+        "average": 26389458.29,
+        "count": 64473760,
+        "maximum": 30299322.58,
+        "minimum": -2450342.801,
+        "name": "GpsTime",
+        "position": 12,
+        "stddev": 10532949.21,
+        "variance": 110943019000000.0
+      }
+    ],
+    "pc:type": "lidar",
+    "pc:units": {
+      "horizontal": "US survey foot",
+      "vertical": "US survey foot"
+    },
+    "provider": "USGS"
+  },
+  "type": "Feature"
+}
diff --git a/extensions/pointcloud/pdal-to-stac.py b/extensions/pointcloud/pdal-to-stac.py
@@ -0,0 +1,69 @@
+#!/usr/bin/env python
+
+# Read 'pdal info --all' output and emit a STAC pc object
+
+import sys
+import json
+import os
+
+
+data = sys.stdin.read()
+
+j = json.loads(data)
+
+def capture_date(pdalinfo):
+    import datetime
+    year = pdalinfo['metadata']['creation_year']
+    day = pdalinfo['metadata']['creation_doy']
+    date = datetime.datetime(int(year), 1, 1) + datetime.timedelta(int(day) - 1)
+    return date.isoformat('T')
+
+def convertGeometry(geom, srs):
+    import ogr
+    import osr
+    in_ref = osr.SpatialReference()
+    in_ref.SetFromUserInput(srs)
+    out_ref = osr.SpatialReference()
+    out_ref.SetFromUserInput('EPSG:4326')
+
+    g = ogr.CreateGeometryFromJson(json.dumps(geom))
+    g.AssignSpatialReference(in_ref)
+    g.TransformTo(out_ref)
+    return json.loads(g.ExportToJson())
+
+
+
+output = {}
+
+try:
+    output['geometry'] = convertGeometry(j['boundary']['boundary_json'],j['metadata']['comp_spatialreference'])
+except KeyError:
+    output['geometry'] = j['stats']['bbox']['EPSG:4326']['boundary']
+
+output['bbox'] = j['stats']['bbox']['EPSG:4326']['bbox']
+output['id'] = os.path.basename(j['filename'])
+output['type'] = 'Feature'
+
+assets = {}
+#assets['thumbnail'] =
+properties = {}
+
+properties['pc:schema'] = j['schema']['dimensions']
+properties['pc:statistics'] = j['stats']['statistic']
+properties['c:id'] = os.path.basename(j['filename'])
+properties['c:description'] = "USGS 3DEP LiDAR"
+properties['provider'] = "USGS"
+properties['license'] = 'LICENSE'
+properties['pc:type'] = 'lidar' # eopc, lidar, radar, sonar
+properties['pc:density'] = j['boundary']['avg_pt_per_sq_unit']
+properties['pc:count'] = j['metadata']['count']
+
+properties['pc:encoding'] = 'LASzip' if bool(j['metadata']['compressed']) else 'None'
+
+properties['datetime'] = capture_date(j)
+
+output['properties'] = properties
+output['assets'] = assets
+
+sys.stdout.write(json.dumps(output,sort_keys=True,
+                  indent=2, separators=(',', ': ')))