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Merge pull request #90 from CartoDB/add-densify-tinmaps

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Add densify / tinmaps functions [14] [15]
This commit is contained in:
Carla
2016-08-30 12:12:26 +02:00
committed by GitHub
parent c3e12036e7 66f4dfa4ea
commit 23a576939b
9 changed files with 335 additions and 0 deletions
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67
src/pg/sql/14_densify.sql Normal file
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--
-- Iterative densification of a set of points using Delaunay triangulation
-- the new points have as assigned value the average value of the 3 vertex (centroid)
--
-- @param geomin - array of geometries (points)
--
-- @param colin - array of numeric values in that points
--
-- @param iterations - integer, number of iterations
--
--
-- Returns: TABLE(geomout geometry, colout numeric)
--
--
CREATE OR REPLACE FUNCTION CDB_Densify(
IN geomin geometry[],
IN colin numeric[],
IN iterations integer
)
RETURNS TABLE(geomout geometry, colout numeric) AS $$
DECLARE
geotemp geometry[];
coltemp numeric[];
i integer;
gs geometry[];
g geometry;
vertex geometry[];
va numeric;
vb numeric;
vc numeric;
center geometry;
centerval numeric;
tmp integer;
BEGIN
geotemp := geomin;
coltemp := colin;
FOR i IN 1..iterations
LOOP
-- generate TIN
WITH a as (SELECT unnest(geotemp) AS e),
b as (SELECT ST_DelaunayTriangles(ST_Collect(a.e),0.001, 0) AS t FROM a),
c as (SELECT (ST_Dump(t)).geom AS v FROM b)
SELECT array_agg(v) INTO gs FROM c;
-- loop cells
FOREACH g IN ARRAY gs
LOOP
-- append centroid
SELECT ST_Centroid(g) INTO center;
geotemp := array_append(geotemp, center);
-- retrieve the value of each vertex
WITH a AS (SELECT (ST_DumpPoints(g)).geom AS v)
SELECT array_agg(v) INTO vertex FROM a;
WITH a AS(SELECT unnest(geotemp) as geo, unnest(coltemp) as c)
SELECT c INTO va FROM a WHERE ST_Equals(geo, vertex[1]);
WITH a AS(SELECT unnest(geotemp) as geo, unnest(coltemp) as c)
SELECT c INTO vb FROM a WHERE ST_Equals(geo, vertex[2]);
WITH a AS(SELECT unnest(geotemp) as geo, unnest(coltemp) as c)
SELECT c INTO vc FROM a WHERE ST_Equals(geo, vertex[3]);
-- calc the value at the center
centerval := (va + vb + vc) / 3;
-- append the value
coltemp := array_append(coltemp, centerval);
END LOOP;
END LOOP;
RETURN QUERY SELECT unnest(geotemp ) as geomout, unnest(coltemp ) as colout;
END;
$$ language plpgsql IMMUTABLE;

43
src/pg/sql/15_tinmap.sql Normal file
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CREATE OR REPLACE FUNCTION CDB_TINmap(
IN geomin geometry[],
IN colin numeric[],
IN iterations integer
)
RETURNS TABLE(geomout geometry, colout numeric) AS $$
DECLARE
p geometry[];
vals numeric[];
gs geometry[];
g geometry;
vertex geometry[];
centerval numeric;
va numeric;
vb numeric;
vc numeric;
coltemp numeric[];
BEGIN
SELECT array_agg(dens.geomout), array_agg(dens.colout) INTO p, vals FROM cdb_crankshaft.CDB_Densify(geomin, colin, iterations) dens;
WITH a as (SELECT unnest(p) AS e),
b as (SELECT ST_DelaunayTriangles(ST_Collect(a.e),0.001, 0) AS t FROM a),
c as (SELECT (ST_Dump(t)).geom AS v FROM b)
SELECT array_agg(v) INTO gs FROM c;
FOREACH g IN ARRAY gs
LOOP
-- retrieve the vertex of each triangle
WITH a AS (SELECT (ST_DumpPoints(g)).geom AS v)
SELECT array_agg(v) INTO vertex FROM a;
-- retrieve the value of each vertex
WITH a AS(SELECT unnest(p) as geo, unnest(vals) as c)
SELECT c INTO va FROM a WHERE ST_Equals(geo, vertex[1]);
WITH a AS(SELECT unnest(p) as geo, unnest(vals) as c)
SELECT c INTO vb FROM a WHERE ST_Equals(geo, vertex[2]);
WITH a AS(SELECT unnest(p) as geo, unnest(vals) as c)
SELECT c INTO vc FROM a WHERE ST_Equals(geo, vertex[3]);
-- calc the value at the center
centerval := (va + vb + vc) / 3;
-- append the value
coltemp := array_append(coltemp, centerval);
END LOOP;
RETURN QUERY SELECT unnest(gs) as geomout, unnest(coltemp ) as colout;
END;
$$ language plpgsql IMMUTABLE;