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Andy Eschbacher
2016-05-11 12:16:41 -04:00
parent 96f67129ab
commit a6752e090d
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doc/boundaries_functions.md
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@@ -16,6 +16,8 @@ timespan (optional) | year(s) to request from (`NULL` (default) gives most recen
#### Returns
A boundary geometry
Value | Description
--- | ---
geom | WKB geometry
@@ -47,6 +49,8 @@ timespan (optional) | year(s) to request from (`NULL` (default) gives most recen
#### Returns
A TEXT boundary geometry id
Value | Description
--- | ---
geometry_id | a string identifier of a geometry in the Boundaries
@@ -74,7 +78,7 @@ timespan (optional) | year(s) to request from (`NULL` (default) gives most recen
#### Returns
A table containing the following properties
A boundary geometry
Key | Description
--- | ---
@@ -112,8 +116,8 @@ A table with the following columns:
Column Name | Description
--- | ---
the_geom | a boundary geometry (e.g., US Census tracts)
geom_ref | a string identifier for the geometry (e.g., the geoid of a US Census tract)
the_geom | a boundary geometry (e.g., US Census tract boundaries)
geom_refs | a string identifier for the geometry (e.g., geoids of US Census tracts)
#### Example
@@ -156,7 +160,7 @@ A table with the following columns:
Column Name | Description
--- | ---
the_geom | a point geometry on a boundary (e.g., a point that lies on a US Census tract)
geom_ref | a string identifier for the geometry (e.g., the geoid of a US Census tract)
geom_refs| a string identifier for the geometry (e.g., the geoid of a US Census tract)
#### Example
@@ -179,94 +183,6 @@ Retrieve all Census tracts intersecting a bounding box around Denver, CO as a JS
http://observatory.cartodb.com/api/v2/sql?q=SELECT * FROM OBS_GetPointsByGeometry(ST_MakeEnvelope(-105.4287704158,39.4600507935,-104.5089737248,40.0901569675,4326), 'us.census.tiger.census_tract', NULL ,'contains')
```
## OBS_GetBoundary(point geometry, boundary_id text)
The ```OBS_GetBoundary(point, boundary_id)``` method returns a boundary geometry defined as overlapping the point geometry and from the desired boundary set (e.g. Census Tracts). See the [Boundary ID glossary table below](below).
#### Arguments
Name | Description
--- | ---
point_geometry | a WGS84 polygon geometry (the_geom)
boundary_id | a boundary identifier from the [Boundary ID glossary table below](below)
timespan (optional) | year(s) to request from (`NULL` (default) gives most recent)
#### Returns
Value | Description
--- | ---
geom | WKB geometry
#### Example
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')
```
<!--
Should add the SQL API call here too
-->
## OBS_GetBoundaryId(point geometry, boundary_id text)
The ```OBS_GetBoundaryId(point, boundary_id)``` returns a unique geometry_id for the boundary geometry that contains a given point geometry. See the [Boundary ID glossary table below](below). The method can be combined with ```OBS_GetBoundaryById(geometry_id)``` to create a point aggregation workflow.
#### Arguments
Name |Description
--- | ---
point | a WGS84 point geometry (the_geom)
boundary_id | a boundary identifier from the [Boundary ID glossary table below](below)
timespan (optional) | year(s) to request from (`NULL` (default) gives most recent)
#### Returns
Value | Description
--- | ---
geometry_id | a string identifier of a geometry in the Boundaries
#### Example
Write the geometry_id that contains the point geometry for every row as a new column in your table
```SQL
UPDATE tablename
SET new_column_name = OBS_GetBoundaryId(the_geom, ' "us.census.tiger".block_group')
```
## OBS_GetBoundaryById(geometry_id text, boundary_id text)
The ```OBS_GetBoundaryById(geometry_id, boundary_id)``` returns the boundary geometry for a unique geometry_id. A geometry_id can be found using the ```OBS_GetBoundaryId(point, boundary_id)``` method described above.
#### Arguments
Name | Description
--- | ---
geometry_id | a string identifier for a Boundary geometry
boundary_id | a boundary identifier from the [Boundary ID glossary table below](below)
timespan (optional) | year(s) to request from (`NULL` (default) gives most recent)
#### Returns
A JSON object containing the following properties
Key | Description
--- | ---
geom | a WGS84 polygon geometry
#### Example
Use a table of geometry_id to select the unique boundaries. Useful with the ```Create Dataset from Query``` option in CartoDB.
```SQL
SELECT OBS_GetBoundaryById(geometry_id) As the_geom, geometry_id
FROM tablename
GROUP BY geometry_id
```
## OBS_GetBoundariesByPointAndRadius(point geometry, radius numeric, boundary_id text)
The ```OBS_GetBoundariesByPointAndRadius(point, radius, boundary_id)``` method returns boundary geometries and their geographical identifiers that intersect (or are contained by) a circle centered on a point with a radius.
@@ -288,7 +204,7 @@ A table with the following columns:
Column Name | Description
--- | ---
the_geom | a boundary geometry (e.g., a US Census tract)
geom_ref | a string identifier for the geometry (e.g., the geoid of a US Census tract)
geom_refs| a string identifier for the geometry (e.g., the geoid of a US Census tract)
#### Example
@@ -323,7 +239,7 @@ A table with the following columns:
Column Name | Description
--- | ---
the_geom | a point geometry (e.g., a point on a US Census tract)
geom_ref | a string identifier for the geometry (e.g., the geoid of a US Census tract)
geom_refs | a string identifier for the geometry (e.g., the geoid of a US Census tract)
#### Example