Files
observatory-extension/src/pg/sql/44_observatory_geometries.sql
2016-04-29 08:52:05 -07:00

495 lines
16 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(Geometry, 4326),
boundary_id text,
time_span text DEFAULT NULL)
RETURNS geometry(Geometry, 4326)
AS $$
DECLARE
boundary geometry(Geometry, 4326);
target_table text;
BEGIN
-- TODO: Check if SRID = 4326, if not transform?
-- if not a point, raise error
IF ST_GeometryType(geom) != 'ST_Point'
THEN
RAISE EXCEPTION 'Invalid geometry type (%), expecting ''ST_Point''', ST_GeometryType(geom);
END IF;
-- choose appropriate table based on time_span
IF time_span IS NULL
THEN
SELECT x.target_tables INTO target_table
FROM cdb_observatory._OBS_SearchTables(boundary_id,
time_span) As x(target_tables,
timespans)
ORDER BY x.timespans DESC
LIMIT 1;
ELSE
-- TODO: modify for only one table returned instead of arbitrarily choosing
-- one with LIMIT 1 (could be conflict between clipped vs non-clipped
-- boundaries in the metadata tables)
SELECT x.target_tables INTO target_table
FROM cdb_observatory._OBS_SearchTables(boundary_id,
time_span) As x(target_tables,
timespans)
WHERE x.timespans = time_span
LIMIT 1;
END IF;
-- if no tables are found, raise notice and return null
IF target_table IS NULL
THEN
RAISE NOTICE 'No boundaries found for ''%'' in ''%''', ST_AsText(geom), boundary_id;
RETURN NULL::geometry;
END IF;
RAISE NOTICE 'target_table: %', target_table;
-- return the first boundary in intersections
EXECUTE format(
'SELECT t.the_geom
FROM observatory.%s As t
WHERE ST_Intersects($1, t.the_geom)
LIMIT 1', target_table)
INTO boundary
USING geom;
RETURN boundary;
END;
$$ 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(Geometry, 4326),
boundary_id text,
time_span text DEFAULT NULL
)
RETURNS text
AS $$
DECLARE
output_id text;
target_table text;
BEGIN
-- If not point, raise error
IF ST_GeometryType(geom) != 'ST_Point'
THEN
RAISE EXCEPTION 'Error: Invalid geometry type (%), expecting ''ST_Point''', ST_GeometryType(geom);
END IF;
-- choose appropriate table based on time_span
IF time_span IS NULL
THEN
SELECT x.target_tables INTO target_table
FROM cdb_observatory._OBS_SearchTables(boundary_id,
time_span) As x(target_tables,
timespans)
ORDER BY x.timespans DESC
LIMIT 1;
ELSE
SELECT x.target_tables INTO target_table
FROM cdb_observatory._OBS_SearchTables(boundary_id,
time_span) As x(target_tables,
timespans)
WHERE x.timespans = time_span
LIMIT 1;
END IF;
-- if no tables are found, raise error
IF target_table IS NULL
THEN
RAISE NOTICE 'Error: No boundaries found for ''%''', boundary_id;
RETURN NULL::text;
END IF;
RAISE NOTICE 'target_table: %', target_table;
-- return name of geometry id column
EXECUTE format(
'SELECT t.geoid
FROM observatory.%s As t
WHERE ST_Intersects($1, t.the_geom)
LIMIT 1', target_table)
INTO output_id
USING geom;
RETURN output_id;
END;
$$ 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 $$
DECLARE
boundary geometry(geometry, 4326);
target_table text;
geoid_colname text;
geom_colname text;
BEGIN
SELECT * INTO geoid_colname, target_table, geom_colname
FROM cdb_observatory._OBS_GetGeometryMetadata(boundary_id);
RAISE NOTICE '%', target_table;
IF target_table IS NULL
THEN
RAISE NOTICE 'No geometries found';
RETURN NULL::geometry;
END IF;
-- retrieve boundary
EXECUTE
format(
'SELECT t.%s
FROM observatory.%I As t
WHERE t.%s = $1
LIMIT 1', geom_colname, target_table, geoid_colname)
INTO boundary
USING geometry_id;
RETURN boundary;
END;
$$ LANGUAGE plpgsql;
-- OBS_GetBoundariesByBBox
--
-- 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_GetBoundariesByBBox(
geom geometry(Geometry, 4326),
boundary_id text,
time_span text DEFAULT NULL,
overlap_type text DEFAULT 'intersects')
RETURNS TABLE(boundary geometry, geom_refs text)
AS $$
DECLARE
boundary geometry(Geometry, 4326);
geom_colname text;
geoid_colname text;
target_table text;
BEGIN
-- check inputs
IF lower(overlap_type) NOT IN ('contains', 'intersects', 'within')
THEN
-- recognized overlap type (map to ST_Contains, ST_Intersects, and ST_Within)
RAISE EXCEPTION 'Overlap type ''%'' is not an accepted type (choose contains, within, intersects)', overlap_type;
ELSIF ST_GeometryType(geom) NOT IN ('ST_Polygon', 'ST_MultiPolygon')
THEN
RAISE EXCEPTION 'Invalid geometry type (%), expecting ''ST_MultiPolygon'' or ''ST_Polygon''', ST_GeometryType(geom);
END IF;
-- TODO: add timespan in search
-- TODO: add overlap info in search
-- TODO: turn this into a function _OBS_GetGeometryMetadata(geo_ref_name, tablename, and geom_colname)
-- SELECT geo_ref_name, tablename, geom_colname INTO a, b, c
-- FROM _OBS_GetGeometryMetadata
SELECT * INTO geoid_colname, target_table, geom_colname
FROM cdb_observatory._OBS_GetGeometryMetadata(boundary_id);
-- if no tables are found, raise notice and return null
IF target_table IS NULL
THEN
RAISE NOTICE 'No boundaries found for bounding box ''%'' in ''%''', ST_AsText(geom), boundary_id;
RETURN QUERY SELECT NULL::geometry, NULL::text;
END IF;
RAISE NOTICE 'target_table: %', target_table;
-- return first boundary in intersections
RETURN QUERY
EXECUTE format(
'SELECT t.%s, t.%s
FROM observatory.%s As t
WHERE ST_%s($1, t.the_geom)
', geom_colname, geoid_colname, target_table, overlap_type)
USING geom;
END;
$$ 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_GetBoundariesByPointAndRadius(
geom geometry(Geometry, 4326), -- point
radius numeric, -- radius in meters
boundary_id text,
time_span text DEFAULT NULL,
overlap_type text DEFAULT 'intersects')
RETURNS TABLE(boundary geometry, geom_refs text)
AS $$
DECLARE
circle_boundary geometry(Geometry, 4326);
BEGIN
circle_boundary := ST_Buffer(geom::geography, radius)::geometry;
RETURN QUERY SELECT *
FROM cdb_observatory.OBS_GetBoundariesByBBox(
circle_boundary,
boundary_id,
time_span);
END;
$$ LANGUAGE plpgsql;
-- OBS_GetPointsByBBox
--
-- Given a bounding box (or 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_GetPointsByBBox(
geom geometry(Geometry, 4326),
boundary_id text,
time_span text DEFAULT NULL,
overlap_type text DEFAULT 'intersects')
RETURNS TABLE(boundary geometry, geom_refs text)
AS $$
DECLARE
boundary geometry(Geometry, 4326);
geom_colname text;
geoid_colname text;
target_table text;
BEGIN
IF lower(overlap_type) NOT IN ('contains', 'within', 'intersects')
THEN
RAISE EXCEPTION 'Overlap type ''%'' is not an accepted type (choose contains, within, or intersects)', overlap_type;
ELSIF ST_GeometryType(geom) NOT IN ('ST_Polygon', 'ST_MultiPolygon')
THEN
RAISE EXCEPTION 'Invalid geometry type (%), expecting ''ST_MultiPolygon'' or ''ST_Polygon''', ST_GeometryType(geom);
END IF;
SELECT * INTO geoid_colname, target_table, geom_colname
FROM cdb_observatory._OBS_GetGeometryMetadata(boundary_id);
-- if no tables are found, raise notice and return null
IF target_table IS NULL
THEN
RAISE NOTICE 'No boundaries found for bounding box ''%'' in ''%''', ST_AsText(geom), boundary_id;
RETURN QUERY SELECT NULL::geometry, NULL::text;
END IF;
RAISE NOTICE 'target_table: %', target_table;
-- return first boundary in intersections
RETURN QUERY
EXECUTE format(
'SELECT ST_PointOnSurface(t.%s) As %s, t.%s
FROM observatory.%s As t
WHERE ST_%s($1, t.the_geom)
', geom_colname, geom_colname, geoid_colname, target_table, overlap_type)
USING geom;
END;
$$ 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(Geometry, 4326), -- point
radius numeric, -- radius in meters
boundary_id text,
time_span text DEFAULT NULL,
overlap_type text DEFAULT 'intersects')
RETURNS TABLE(boundary geometry, geom_refs text)
AS $$
BEGIN
RETURN QUERY SELECT *
FROM cdb_observatory.OBS_GetPointsByBBox(
ST_Buffer(geom::geography, radius)::geometry,
boundary_id,
time_span,
overlap_type);
END;
$$ LANGUAGE plpgsql;
-- _OBS_GetGeometryMetadata()
-- TODO: add timespan in search
-- TODO: add choice of clipped versus not clipped
CREATE OR REPLACE FUNCTION cdb_observatory._OBS_GetGeometryMetadata(boundary_id text)
RETURNS table(geoid_colname text, target_table text, geom_colname text)
AS $$
BEGIN
RETURN QUERY
EXECUTE
format($string$
SELECT geoid_ct.colname As geoid_colname,
tablename,
geom_ct.colname As geom_colname
FROM observatory.obs_column_table As geoid_ct,
observatory.obs_table As geom_t,
observatory.obs_column_table As geom_ct,
observatory.obs_column As geom_c
WHERE geoid_ct.column_id
IN (
SELECT source_id
FROM observatory.obs_column_to_column
WHERE reltype = 'geom_ref'
AND target_id = '%s'
)
AND geoid_ct.table_id = geom_t.id and
geom_t.id = geom_ct.table_id and
geom_ct.column_id = geom_c.id and
geom_c.type ILIKE 'geometry'
-- TODO: filter by clipped vs. not so appropriate tablename are unique
-- so the limit 1 can be removed
LIMIT 1
$string$, boundary_id);
END;
$$ LANGUAGE plpgsql;