Add new docs folder structure

2018-02-21 16:48:37 +01:00
parent 2183b7fc26
commit e07ee0b882
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+- Insert all Census Tracts from Lower Manhattan and nearby areas within the supplied bounding box to a table named `manhattan_census_tracts` which has columns `the_geom` (geometry) and `geom_refs` (text).
+
+```sql
+INSERT INTO manhattan_census_tracts(the_geom, geom_refs)
+SELECT *
+FROM OBS_GetBoundariesByGeometry(
+       ST_MakeEnvelope(-74.0251922607,40.6945658517,
+                      -73.9651107788,40.7377626342,
+                      4326),
+       'us.census.tiger.census_tract')
+```
+
+- Insert points that lie on Census Tracts from Lower Manhattan and nearby areas within the supplied bounding box to a table named `manhattan_tract_points` which has columns `the_geom` (geometry) and `geom_refs` (text).
+
+```sql
+INSERT INTO manhattan_tract_points (the_geom, geom_refs)
+SELECT *
+FROM OBS_GetPointsByGeometry(
+       ST_MakeEnvelope(-74.0251922607,40.6945658517,
+                       -73.9651107788,40.7377626342,
+                       4326),
+       'us.census.tiger.census_tract')
+```
+
+
+- Overwrite a point geometry with a boundary geometry that contains it in your table
+
+```SQL
+UPDATE tablename
+SET the_geom = OBS_GetBoundary(the_geom, 'us.census.tiger.block_group')
+```
+
+
+- Write the US Census block group geoid that contains the point geometry for every row as a new column in your table.
+
+```SQL
+UPDATE tablename
+SET geometry_id = OBS_GetBoundaryId(the_geom, 'us.census.tiger.block_group')
+```
+
+
+- Use a table of `geometry_id`s (e.g., geoid from the U.S. Census) to select the unique boundaries that they correspond to and insert into a table called, `overlapping_polygons`. This is a useful method for creating new choropleths of aggregate data.
+
+```SQL
+INSERT INTO overlapping_polygons (the_geom, geometry_id, point_count)
+SELECT
+  OBS_GetBoundaryById(geometry_id, 'us.census.tiger.county') As the_geom,
+  geometry_id,
+  count(*)
+FROM tablename
+GROUP BY geometry_id
+```
+
+
+- Insert into table `denver_census_tracts` the census tract boundaries and geom_refs of census tracts which intersect within 10 miles of downtown Denver, Colorado.
+
+```sql
+INSERT INTO denver_census_tracts(the_geom, geom_refs)
+SELECT *
+FROM OBS_GetBoundariesByPointAndRadius(
+  CDB_LatLng(39.7392, -104.9903), -- Denver, Colorado
+  10000 * 1.609, -- 10 miles (10km * conversion to miles)
+  'us.census.tiger.census_tract')
+```
+
+
+- Insert into table `denver_tract_points` points on US census tracts and their corresponding geoids for census tracts which intersect within 10 miles of downtown Denver, Colorado, USA.
+
+```sql
+INSERT INTO denver_tract_points(the_geom, geom_refs)
+SELECT *
+FROM OBS_GetPointsByPointAndRadius(
+  CDB_LatLng(39.7392, -104.9903), -- Denver, Colorado
+  10000 * 1.609, -- 10 miles (10km * conversion to miles)
+  'us.census.tiger.census_tract')
+```