Files
observatory-extension/src/pg/sql/44_observatory_geometries.sql
2017-01-10 02:28:38 +00:00

416 lines
14 KiB
PL/PgSQL

-- Data Observatory -- Welcome to the Future
-- These Data Observatory functions provide access to boundary polyons (and
-- their ids) such as those available through the US Census Tiger, Who's on
-- First, the Spanish Census, and so on
-- OBS_GetBoundary
--
-- Returns the boundary polygon(s) that overlap with the input point geometry.
-- From an input point geometry, find the boundary which intersects with the
-- centroid of the input geometry
-- Inputs:
-- geom geometry: input point geometry
-- boundary_id text: source id of boundaries
-- see function OBS_ListGeomColumns for all avaiable
-- boundary ids
-- time_span text: time span that the geometries were collected (optional)
--
-- Output:
-- boundary geometry: geometry boundary that intersects with geom, is at the
-- resolution requested with boundary_id, and time_span
--
CREATE OR REPLACE FUNCTION cdb_observatory.OBS_GetBoundary(
geom geometry(Point, 4326),
boundary_id text,
time_span text DEFAULT NULL)
RETURNS geometry(Geometry, 4326)
AS $$
DECLARE
boundary geometry(Geometry, 4326);
target_table text;
BEGIN
-- TODO: Check if SRID = 4326, if not transform?
-- if not a point, raise error
IF ST_GeometryType(geom) != 'ST_Point'
THEN
RAISE EXCEPTION 'Invalid geometry type (%), expecting ''ST_Point''', ST_GeometryType(geom);
END IF;
-- return the first boundary in intersections
EXECUTE $query$
SELECT * FROM cdb_observatory._OBS_GetBoundariesByGeometry($1, $2, $3) LIMIT 1
$query$ INTO boundary
USING geom, boundary_id, time_span;
RETURN boundary;
END;
$$ LANGUAGE plpgsql;
-- OBS_GetBoundaryId
--
-- retrieves the boundary identifier (e.g., '36047' = Kings County/Brooklyn, NY)
-- corresponding to the location geom and boundary types (e.g.,
-- us.census.tiger.county)
-- Inputs:
-- geom geometry: location where the boundary is requested to overlap with
-- boundary_id text: source id of boundaries (e.g., us.census.tiger.county)
-- see function OBS_ListGeomColumns for all avaiable
-- boundary ids
-- time_span text: time span that the geometries were collected (optional)
--
-- Output:
-- geometry_id text: identifier of the geometry which overlaps with the input
-- point geom in the table corresponding to boundary_id and
-- time_span
--
CREATE OR REPLACE FUNCTION cdb_observatory.OBS_GetBoundaryId(
geom geometry(Point, 4326),
boundary_id text,
time_span text DEFAULT NULL
)
RETURNS text
AS $$
DECLARE
result TEXT;
BEGIN
EXECUTE $query$
SELECT geom_refs FROM cdb_observatory._OBS_GetBoundariesByGeometry(
$1, $2, $3) LIMIT 1
$query$
INTO result
USING geom, boundary_id, time_span;
RETURN result;
END;
$$ LANGUAGE plpgsql;
-- OBS_GetBoundaryById
--
-- Given a geometry reference (e.g., geoid for US Census), and it's geometry
-- level (see OBS_ListGeomColumns() for all available boundary ids), give back
-- the boundary that corresponds to that geometry_id, boundary_id, and
-- time_span
-- Inputs:
-- geometry_id text: geometry id of the requested boundary
-- boundary_id text: source id of boundaries (e.g., us.census.tiger.county)
-- see function OBS_ListGeomColumns for all avaiable
-- boundary ids
-- time_span text: time span that the geometries were collected (optional)
--
-- Output:
-- boundary geometry: geometry boundary that matches geometry_id, is at the
-- resolution requested with boundary_id, and time_span
--
CREATE OR REPLACE FUNCTION cdb_observatory.OBS_GetBoundaryById(
geometry_id text, -- ex: '36047'
boundary_id text, -- ex: 'us.census.tiger.county'
time_span text DEFAULT NULL -- ex: '2009'
)
RETURNS geometry(geometry, 4326)
AS $$
DECLARE
result GEOMETRY;
BEGIN
EXECUTE $query$
SELECT (data->0->>'value')::Geometry
FROM cdb_observatory.OBS_GetData(
ARRAY[$1],
cdb_observatory.OBS_GetMeta(
ST_MakeEnvelope(-180, -90, 180, 90, 4326),
('[{"geom_id": "' || $2 || '"}]')::JSON))
$query$
INTO result
USING geometry_id, boundary_id;
RETURN result;
END;
$$ LANGUAGE plpgsql;
-- _OBS_GetBoundariesByGeometry
-- internal function for retrieving geometries based on an input geometry
-- see OBS_GetBoundariesByGeometry or OBS_GetBoundariesByPointAndRadius for
-- more information
CREATE OR REPLACE FUNCTION cdb_observatory._OBS_GetBoundariesByGeometry(
geom geometry(Geometry, 4326),
boundary_id text,
time_span text DEFAULT NULL,
overlap_type text DEFAULT NULL)
RETURNS TABLE (
the_geom geometry,
geom_refs text
) AS $$
DECLARE
meta JSON;
BEGIN
overlap_type := COALESCE(overlap_type, 'intersects');
-- check inputs
IF lower(overlap_type) NOT IN ('contains', 'intersects', 'within')
THEN
-- recognized overlap type (map to ST_Contains, ST_Intersects, and ST_Within)
RAISE EXCEPTION 'Overlap type ''%'' is not an accepted type (choose intersects, within, or contains)', overlap_type;
END IF;
EXECUTE $query$
SELECT cdb_observatory.OBS_GetMeta($1, JSON_Build_Array(JSON_Build_Object(
'geom_id', $2, 'geom_timespan', $3)))
$query$
INTO meta
USING geom, boundary_id, time_span;
IF meta->0->>'geom_id' IS NULL THEN
RETURN QUERY EXECUTE 'SELECT NULL::Geometry, NULL::Text LIMIT 0';
RETURN;
END IF;
-- return first boundary in intersections
RETURN QUERY EXECUTE $query$
SELECT (data->0->>'value')::Geometry the_geom, data->0->>'geomref' geom_refs
FROM cdb_observatory.OBS_GetData(
ARRAY[($1, 1)::geomval], $2, False
)
$query$ USING geom, meta;
RETURN;
END;
$$ LANGUAGE plpgsql;
-- OBS_GetBoundariesByGeometry
--
-- Given a bounding box (or a polygon), and it's geometry level (see
-- OBS_ListGeomColumns() for all available boundary ids), give back the
-- boundaries that are contained within the bounding box polygon and the
-- associated geometry ids
-- Inputs:
-- geom geometry: bounding box (or polygon) of the region of interest
-- boundary_id text: source id of boundaries (e.g., us.census.tiger.county)
-- see function OBS_ListGeomColumns for all avaiable
-- boundary ids
-- time_span text: time span that the geometries were collected (optional)
--
-- Output:
-- table with the following columns
-- boundary geometry: geometry boundary that is contained within the input
-- bounding box at the requested geometry level
-- with boundary_id, and time_span
-- geom_refs text: geometry identifiers (e.g., geoid for the US Census)
--
CREATE OR REPLACE FUNCTION cdb_observatory.OBS_GetBoundariesByGeometry(
geom geometry(Geometry, 4326),
boundary_id text,
time_span text DEFAULT NULL,
overlap_type text DEFAULT NULL)
RETURNS TABLE(the_geom geometry, geom_refs text)
AS $$
BEGIN
RETURN QUERY SELECT *
FROM cdb_observatory._OBS_GetBoundariesByGeometry(
geom,
boundary_id,
time_span,
overlap_type
);
RETURN;
END;
$$ LANGUAGE plpgsql;
-- OBS_GetBoundariesByPointAndRadius
--
-- Given a point and radius, and it's geometry level (see
-- OBS_ListGeomColumns() for all available boundary ids), give back the
-- boundaries that are contained within the point buffered by radius meters and
-- the associated geometry ids
-- Inputs:
-- geom geometry: point geometry centered on area of interest
-- radius numeric: radius (in meters) of a circle centered on geom for
-- selecting polygons
-- boundary_id text: source id of boundaries (e.g., us.census.tiger.county)
-- see function OBS_ListGeomColumns for all avaiable
-- boundary ids
-- time_span text: time span that the geometries were collected (optional)
--
-- Output:
-- table with the following columns
-- boundary geometry: geometry boundary that is contained within the input
-- bounding box at the requested geometry level
-- with boundary_id, and time_span
-- geom_refs text: geometry identifiers (e.g., geoid for the US Census)
--
-- TODO: move to ST_DWithin instead of buffer + intersects?
CREATE OR REPLACE FUNCTION cdb_observatory.OBS_GetBoundariesByPointAndRadius(
geom geometry(Point, 4326), -- point
radius numeric, -- radius in meters
boundary_id text,
time_span text DEFAULT NULL,
overlap_type text DEFAULT NULL)
RETURNS TABLE(the_geom geometry, geom_refs text)
AS $$
DECLARE
circle_boundary geometry(Geometry, 4326);
BEGIN
IF ST_GeometryType(geom) != 'ST_Point'
THEN
RAISE EXCEPTION 'Input geometry ''%'' is not a point', ST_AsText(geom);
ELSE
circle_boundary := ST_Buffer(geom::geography, radius)::geometry;
END IF;
RETURN QUERY SELECT *
FROM cdb_observatory._OBS_GetBoundariesByGeometry(
circle_boundary,
boundary_id,
time_span,
overlap_type);
RETURN;
END;
$$ LANGUAGE plpgsql;
-- _OBS_GetPointsByGeometry
CREATE OR REPLACE FUNCTION cdb_observatory._OBS_GetPointsByGeometry(
geom geometry(Geometry, 4326),
boundary_id text,
time_span text DEFAULT NULL,
overlap_type text DEFAULT NULL)
RETURNS TABLE(the_geom geometry, geom_refs text)
AS $$
DECLARE
boundary geometry(Geometry, 4326);
geom_colname text;
geoid_colname text;
target_table text;
BEGIN
overlap_type := COALESCE(overlap_type, 'intersects');
IF lower(overlap_type) NOT IN ('contains', 'within', 'intersects')
THEN
RAISE EXCEPTION 'Overlap type ''%'' is not an accepted type (choose intersects, within, or contains)', overlap_type;
ELSIF ST_GeometryType(geom) NOT IN ('ST_Polygon', 'ST_MultiPolygon')
THEN
RAISE EXCEPTION 'Invalid geometry type (%), expecting ''ST_MultiPolygon'' or ''ST_Polygon''', ST_GeometryType(geom);
END IF;
-- return first boundary in intersections
RETURN QUERY EXECUTE $query$
SELECT ST_PointOnSurface(the_geom), geom_refs
FROM cdb_observatory._OBS_GetBoundariesByGeometry($1, $2)
$query$ USING geom, boundary_id;
RETURN;
END;
$$ LANGUAGE plpgsql;
-- OBS_GetPointsByGeometry
--
-- Given a polygon, and it's geometry level (see
-- OBS_ListGeomColumns() for all available boundary ids), give back a point
-- which lies in a boundary from the requested geometry level that is contained
-- within the bounding box polygon and the associated geometry ids
--
-- Inputs:
-- geom geometry: bounding box (or polygon) of the region of interest
-- boundary_id text: source id of boundaries (e.g., us.census.tiger.county)
-- see function OBS_ListGeomColumns for all avaiable
-- boundary ids
-- time_span text: time span that the geometries were collected (optional)
--
-- Output:
-- table with the following columns
-- boundary geometry: point that lies on a boundary that is contained within
-- the input bounding box at the requested geometry
-- level with boundary_id, and time_span
-- geom_refs text: geometry identifiers (e.g., geoid for the US Census)
--
CREATE OR REPLACE FUNCTION cdb_observatory.OBS_GetPointsByGeometry(
geom geometry(Geometry, 4326),
boundary_id text,
time_span text DEFAULT NULL,
overlap_type text DEFAULT NULL)
RETURNS TABLE(the_geom geometry, geom_refs text)
AS $$
BEGIN
RETURN QUERY SELECT *
FROM cdb_observatory._OBS_GetPointsByGeometry(
geom,
boundary_id,
time_span,
overlap_type);
RETURN;
END;
$$ LANGUAGE plpgsql;
-- OBS_GetBoundariesByPointAndRadius
--
-- Given a point and radius, and it's geometry level (see
-- OBS_ListGeomColumns() for all available boundary ids), give back the
-- boundaries that are contained within the point buffered by radius meters and
-- the associated geometry ids
-- Inputs:
-- geom geometry: point geometry centered on area of interest
-- radius numeric: radius (in meters) of a circle centered on geom for
-- selecting polygons
-- boundary_id text: source id of boundaries (e.g., us.census.tiger.county)
-- see function OBS_ListGeomColumns for all avaiable
-- boundary ids
-- time_span text: time span that the geometries were collected (optional)
--
-- Output:
-- table with the following columns
-- boundary geometry: geometry boundary that is contained within the input
-- bounding box at the requested geometry level
-- with boundary_id, and time_span
-- geom_refs text: geometry identifiers (e.g., geoid for the US Census)
--
CREATE OR REPLACE FUNCTION cdb_observatory.OBS_GetPointsByPointAndRadius(
geom geometry(Point, 4326), -- point
radius numeric, -- radius in meters
boundary_id text,
time_span text DEFAULT NULL,
overlap_type text DEFAULT NULL)
RETURNS TABLE(the_geom geometry, geom_refs text)
AS $$
DECLARE
circle_boundary geometry(Geometry, 4326);
BEGIN
IF ST_GeometryType(geom) != 'ST_Point'
THEN
RAISE EXCEPTION 'Input geometry ''%'' is not a point', ST_AsText(geom);
ELSE
circle_boundary := ST_Buffer(geom::geography, radius)::geometry;
END IF;
RETURN QUERY SELECT *
FROM cdb_observatory._OBS_GetPointsByGeometry(
ST_Buffer(geom::geography, radius)::geometry,
boundary_id,
time_span,
overlap_type);
RETURN;
END;
$$ LANGUAGE plpgsql;