Addition of coverage_tile constraint for raster. Ticket #2148

git-svn-id: http://svn.osgeo.org/postgis/trunk@10835 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/NEWS b/NEWS
index 6375a03db378312fe6dbf5552b8d32d484728584..d45a9d936e012a71255bcdfc6264f107b5007ac3 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -100,6 +100,8 @@ PostGIS 2.1.0
     and ST_SnapToGrid() no longer require an SRID
   - #2141, More verbose output when constraints fail to be added
     to a raster column
+  - #2069, Added parameters to ST_Tile(raster) to control padding of tiles
+  - #2148, Addition of coverage_tile constraint for raster
 
 * Fixes *
 

diff --git a/raster/rt_pg/rtpostgis.sql.in.c b/raster/rt_pg/rtpostgis.sql.in.c
index 12f268c058649e63be406147dc8f5b7563ca0371..396d0a4d60b6877c8874b7096f4c73b339971db3 100644 (file)
--- a/raster/rt_pg/rtpostgis.sql.in.c
+++ b/raster/rt_pg/rtpostgis.sql.in.c
@@ -6581,6 +6581,84 @@ CREATE OR REPLACE FUNCTION _drop_raster_constraint_spatially_unique(rastschema n
        LANGUAGE 'sql' VOLATILE STRICT
        COST 100;
 
+CREATE OR REPLACE FUNCTION _raster_constraint_info_coverage_tile(rastschema name, rasttable name, rastcolumn name)
+       RETURNS boolean AS $$
+       SELECT
+               TRUE
+       FROM pg_class c, pg_namespace n, pg_attribute a, pg_constraint s
+       WHERE n.nspname = $1
+               AND c.relname = $2
+               AND a.attname = $3
+               AND a.attrelid = c.oid
+               AND s.connamespace = n.oid
+               AND s.conrelid = c.oid
+               AND a.attnum = ANY (s.conkey)
+               AND s.consrc LIKE '%st_iscoveragetile(%';
+       $$ LANGUAGE sql STABLE STRICT
+  COST 100;
+
+CREATE OR REPLACE FUNCTION _add_raster_constraint_coverage_tile(rastschema name, rasttable name, rastcolumn name)
+       RETURNS boolean AS $$
+       DECLARE
+               fqtn text;
+               cn name;
+               sql text;
+
+               _scalex double precision;
+               _scaley double precision;
+               _skewx double precision;
+               _skewy double precision;
+               _tilewidth integer;
+               _tileheight integer;
+               _alignment boolean;
+
+               _covextent geometry;
+               _covrast raster;
+       BEGIN
+               fqtn := '';
+               IF length($1) > 0 THEN
+                       fqtn := quote_ident($1) || '.';
+               END IF;
+               fqtn := fqtn || quote_ident($2);
+
+               cn := 'enforce_coverage_tile_' || $3;
+
+               -- metadata
+               BEGIN
+                       sql := 'WITH foo AS (SELECT ST_Metadata(' || quote_ident($3) || ') AS meta, ST_ConvexHull(' || quote_ident($3) || ') AS hull FROM ' || fqtn || ') SELECT max((meta).scalex), max((meta).scaley), max((meta).skewx), max((meta).skewy), max((meta).width), max((meta).height), ST_Union(hull) FROM foo';
+                       EXECUTE sql INTO _scalex, _scaley, _skewx, _skewy, _tilewidth, _tileheight, _covextent;
+               EXCEPTION WHEN OTHERS THEN
+               END;
+
+               -- rasterize extent
+               BEGIN
+                       _covrast := ST_AsRaster(_covextent, _scalex, _scaley, '8BUI', 1, 0, NULL, NULL, _skewx, _skewy);
+                       IF _covrast IS NULL THEN
+                               RAISE NOTICE 'Unable to create coverage raster. Cannot add coverage tile constraint';
+                               RETURN FALSE;
+                       END IF;
+
+                       -- remove band
+                       _covrast := ST_MakeEmptyRaster(_covrast);
+               EXCEPTION WHEN OTHERS THEN
+                       RAISE NOTICE 'Unable to create coverage raster. Cannot add coverage tile constraint';
+                       RETURN FALSE;
+               END;
+
+               sql := 'ALTER TABLE ' || fqtn ||
+                       ' ADD CONSTRAINT ' || quote_ident(cn) ||
+                       ' CHECK (st_iscoveragetile(' || quote_ident($3) || ', ''' || _covrast || '''::raster, ' || _tilewidth || ', ' || _tileheight || '))';
+               RETURN _add_raster_constraint(cn, sql);
+       END;
+       $$ LANGUAGE 'plpgsql' VOLATILE STRICT
+       COST 100;
+
+CREATE OR REPLACE FUNCTION _drop_raster_constraint_coverage_tile(rastschema name, rasttable name, rastcolumn name)
+       RETURNS boolean AS
+       $$ SELECT _drop_raster_constraint($1, $2, 'enforce_coverage_tile_' || $3) $$
+       LANGUAGE 'sql' VOLATILE STRICT
+       COST 100;
+
 CREATE OR REPLACE FUNCTION _raster_constraint_info_regular_blocking(rastschema name, rasttable name, rastcolumn name)
        RETURNS boolean
        AS $$