Add US Census Bureau layers

layers/census-bureau/README.md

@@ -0,0 +1,38 @@
+from the US Census Bureau:
+
+https://www.census.gov/geographies/mapping-files/time-series/geo/cartographic-boundary.html
+
+more description here:
+
+https://www.census.gov/programs-surveys/geography/technical-documentation/naming-convention/cartographic-boundary-file.html
+
+Including the following:
+
+> # File Naming Convention
+> ## 2013 to Present Files
+> 
+> The cartographic boundary files are named cb_yyyy_ss_<entity>_rr.zip where:
+> 
+> * yyyy = 4 digit year
+> * ss = state FIPS code or 'us' for a national level file
+> * entity = the entity name
+> * rr = resolution level
+>    * 500k = 1:500,000
+>    * 5m = 1:5,000,000
+>    * 20m = 1:20,000,000
+
+I prefer the KML options when available since OpenLayers doesn't [citation
+needed?] have built-in support for shapefiles (.shp)? That said, we also do
+transform KML to GeoJSON to be able to edit more easily (and it's sometimes good
+for a smaller file size).
+
+For more information, see e.g.:
+
+https://indicatrix.org/post/shapefiles-in-openlayers/
+
+Census Bureau data appears to be using a different (US-centric, possibly?)
+projection; this may require more work to be accurate going forward.
+
+https://gis.stackexchange.com/a/310949
+
+https://epsg.io/4269

layers/census-bureau/cleanup_data.py

@@ -0,0 +1,47 @@
+#!/usr/bin/python3
+
+import sys
+import json
+
+with open(sys.argv[1]) as f:
+    data = json.load(f)
+
+# {
+#     "type": "FeatureCollection",
+#     "name": "cb_2022_us_county_20m",
+#     "crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:OGC:1.3:CRS84" } },
+#     "features": [
+#          {
+#              "type": "Feature",
+#              "properties": {
+#                  "Name": "<at><openparen>Autauga<closeparen>",
+#                  "Description": "<center><table><tr><th colspan='2' align='center'><em>Attributes</em></th></tr><tr bgcolor=\"#E3E3F3\"> <th>STATEFP</th> <td>01</td> </tr><tr bgcolor=\"\"> <th>COUNTYFP</th> <td>001</td> </tr><tr bgcolor=\"#E3E3F3\"> <th>COUNTYNS</th> <td>00161526</td> </tr><tr bgcolor=\"\"> <th>AFFGEOID</th> <td>0500000US01001</td> </tr><tr bgcolor=\"#E3E3F3\"> <th>GEOID</th> <td>01001</td> </tr><tr bgcolor=\"\"> <th>NAME</th> <td>Autauga</td> </tr><tr bgcolor=\"#E3E3F3\"> <th>NAMELSAD</th> <td>Autauga County</td> </tr><tr bgcolor=\"\"> <th>STUSPS</th> <td>AL</td> </tr><tr bgcolor=\"#E3E3F3\"> <th>STATE_NAME</th> <td>Alabama</td> </tr><tr bgcolor=\"\"> <th>LSAD</th> <td>06</td> </tr><tr bgcolor=\"#E3E3F3\"> <th>ALAND</th> <td>1539631461</td> </tr><tr bgcolor=\"\"> <th>AWATER</th> <td>25677536</td> </tr></table></center>"
+#              },
+#              "geometry": {
+#                  "type": "Polygon",
+#                  "coordinates": [
+#                      [
+#                          [
+#                              -86.917595,
+#                              32.664169,
+#                              0.0
+#                          ],
+#                          ...
+#                      ]
+#                  ]
+#              }
+#          },
+#          [...]
+#     ]
+# }
+
+# len("<at><openparen>") == 15
+# len("<closeparen>") == 12
+# "<at><openparen>Autauga<closeparen>"[15:-12] == "Autauga"
+
+for feature in data['features']:
+    # del feature['properties']['Description']
+    feature['properties']['Name'] = feature['properties']['Name'][15:-12]
+
+with open(sys.argv[1], 'w') as f:
+    json.dump(data, f)

layers/census-bureau/get_data.sh

@@ -0,0 +1,17 @@
+#!/bin/sh
+
+for resolution in 20m 5m; do
+    curl --silent --remote-name https://www2.census.gov/geo/tiger/GENZ2022/shp/cb_2022_us_county_${resolution}.zip
+    unzip cb_2022_us_county_${resolution}.zip
+    ogr2ogr -f GeoJSON us-counties-${resolution}.geojson cb_2022_us_county_${resolution}.shp
+    sed -i '/^"crs":/d' us-counties-${resolution}.geojson # TODO: handle this projection properly
+    rm cb_2022_us_county_${resolution}.*
+    # python cleanup_data.py us-counties-${resolution}.geojson # Only needed for KML files
+done
+
+curl --silent --remote-name https://www2.census.gov/geo/tiger/GENZ2022/shp/cb_2022_us_unsd_500k.zip
+unzip cb_2022_us_unsd_500k.zip
+ogr2ogr -f GeoJSON us-school-districts.geojson cb_2022_us_unsd_500k.shp
+sed -i '/^"crs":/d' us-school-districts.geojson # TODO: handle this projection properly
+rm cb_2022_us_unsd_500k.*
+# TODO: some kind of cleanup to save space?

layers/census-bureau/index.js

@@ -0,0 +1,63 @@
+import GeoJSON from 'ol/format/GeoJSON.js';
+import VectorLayer from 'ol/layer/Vector.js';
+import VectorSource from 'ol/source/Vector.js';
+
+import counties20m from './us-counties-20m.geojson?url';
+import counties5m from './us-counties-5m.geojson?url';
+import schoolDistricts from './us-school-districts.geojson?url';
+
+import { Fill, Stroke, Style, Text } from 'ol/style.js';
+
+function style(feature){
+    return new Style({
+        text: new Text({
+            text: feature.get('NAME'),
+        }),
+        fill: new Fill({
+            color: 'rgba(255,255,255,0.4)',
+        }),
+        stroke: new Stroke({
+            color: '#3399CC',
+            width: 1.25,
+        }),
+    });
+}
+
+const layers = {
+    name: "US Census Bureau Data",
+    layers: [
+        {
+            name: "All Counties (2022; low-res)",
+            layer: new VectorLayer({
+                source: new VectorSource({
+                    url: counties20m,
+                    format: new GeoJSON(),
+                }),
+                style: style,
+            }),
+        },
+        {
+            name: "All Counties (2022; medium-res)",
+            layer: new VectorLayer({
+                source: new VectorSource({
+                    url: counties5m,
+                    format: new GeoJSON(),
+                }),
+                style: style,
+            }),
+        },
+        {
+            name: "School Districts (2022; unreasonably large)",
+            layer: new VectorLayer({
+                source: new VectorSource({
+                    url: schoolDistricts,
+                    format: new GeoJSON(),
+                    // TODO: this probably uses projection 'EPSG:4326'
+                }),
+                style: style,
+            }),
+        },
+    ],
+};
+
+export default layers;

layers/index.js

@@ -7,6 +7,7 @@ import amtrakLayer from './amtrak/layer.js';
 import arenasLayer from './nhl-arenas/layer.js';
 import bikepackingLayer from './bikepacking/layer.js';
 import chains from './chains/index.js';
+import census_bureau from './census-bureau/index.js';
 
 const layerCategories = [
     { // Base maps
@@ -70,7 +71,8 @@ const layerCategories = [
             },
         ]
     },
-    chains
+    chains,
+    census_bureau,
 ];
 
 export default layerCategories;