Addition of ST_IsCoverageTile() to tell if tile is part of a coverage

git-svn-id: http://svn.osgeo.org/postgis/trunk@10834 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/raster/rt_pg/rtpostgis.sql.in.c b/raster/rt_pg/rtpostgis.sql.in.c
index 3b6a07fa914fbb1bb94a08d5b5f17374f8d77b89..12f268c058649e63be406147dc8f5b7563ca0371 100644 (file)
--- a/raster/rt_pg/rtpostgis.sql.in.c
+++ b/raster/rt_pg/rtpostgis.sql.in.c
@@ -5236,6 +5236,107 @@ CREATE OR REPLACE FUNCTION st_notsamealignmentreason(rast1 raster, rast2 raster)
        AS 'MODULE_PATHNAME', 'RASTER_notSameAlignmentReason'
        LANGUAGE 'c' IMMUTABLE STRICT;
 
+-----------------------------------------------------------------------
+-- ST_IsCoverageTile
+-----------------------------------------------------------------------
+
+CREATE OR REPLACE FUNCTION st_iscoveragetile(rast raster, coverage raster, tilewidth integer, tileheight integer)
+       RETURNS boolean
+       AS $$
+       DECLARE
+               _rastmeta record;
+               _covmeta record;
+               cr record;
+               max integer[];
+               tile integer[];
+               edge integer[];
+       BEGIN
+               IF NOT ST_SameAlignment(rast, coverage) THEN
+                       RAISE NOTICE 'Raster and coverage are not aligned';
+                       RETURN FALSE;
+               END IF;
+
+               _rastmeta := ST_Metadata(rast);
+               _covmeta := ST_Metadata(coverage);
+
+               -- get coverage grid coordinates of upper-left of rast
+               cr := ST_WorldToRasterCoord(coverage, _rastmeta.upperleftx, _rastmeta.upperlefty);
+
+               -- rast is not part of coverage
+               IF
+                       (cr.columnx < 1 OR cr.columnx > _covmeta.width) OR
+                       (cr.rowy < 1 OR cr.rowy > _covmeta.height)
+               THEN
+                       RAISE NOTICE 'Raster is not in the coverage';
+                       RETURN FALSE;
+               END IF;
+
+               -- rast isn't on the coverage's grid
+               IF
+                       ((cr.columnx - 1) % tilewidth != 0) OR
+                       ((cr.rowy - 1) % tileheight != 0)
+               THEN
+                       RAISE NOTICE 'Raster is not aligned to tile grid of coverage';
+                       RETURN FALSE;
+               END IF;
+
+               -- max # of tiles on X and Y for coverage
+               max[0] := ceil(_covmeta.width::double precision / tilewidth::double precision)::integer;
+               max[1] := ceil(_covmeta.height::double precision / tileheight::double precision)::integer;
+
+               -- tile # of rast in coverge
+               tile[0] := (cr.columnx / tilewidth) + 1;
+               tile[1] := (cr.rowy / tileheight) + 1;
+
+               -- inner tile
+               IF tile[0] < max[0] AND tile[1] < max[1] THEN
+                       IF
+                               (_rastmeta.width != tilewidth) OR
+                               (_rastmeta.height != tileheight)
+                       THEN
+                               RAISE NOTICE 'Raster width/height is invalid for interior tile of coverage';
+                               RETURN FALSE;
+                       ELSE
+                               RETURN TRUE;
+                       END IF;
+               END IF;
+
+               -- get edge tile width and height
+               edge[0] := _covmeta.width - ((max[0] - 1) * tilewidth);
+               edge[1] := _covmeta.height - ((max[1] - 1) * tileheight);
+
+               -- edge tile not of expected tile size
+               -- right and bottom
+               IF tile[0] = max[0] AND tile[1] = max[1] THEN
+                       IF
+                               _rastmeta.width != edge[0] OR
+                               _rastmeta.height != edge[1]
+                       THEN
+                               RAISE NOTICE 'Raster width/height is invalid for right-most AND bottom-most tile of coverage';
+                               RETURN FALSE;
+                       END IF;
+               ELSEIF tile[0] = max[0] THEN
+                       IF
+                               _rastmeta.width != edge[0] OR
+                               _rastmeta.height != tileheight
+                       THEN
+                               RAISE NOTICE 'Raster width/height is invalid for right-most tile of coverage';
+                               RETURN FALSE;
+                       END IF;
+               ELSE
+                       IF
+                               _rastmeta.width != tilewidth OR
+                               _rastmeta.height != edge[1]
+                       THEN
+                               RAISE NOTICE 'Raster width/height is invalid for bottom-most tile of coverage';
+                               RETURN FALSE;
+                       END IF;
+               END IF;
+
+               RETURN TRUE;
+       END;
+       $$ LANGUAGE 'plpgsql' IMMUTABLE STRICT;
+
 -----------------------------------------------------------------------
 -- ST_Intersects(raster, raster)
 -----------------------------------------------------------------------