Changes between Version 54 and Version 55 of WKTRaster/SpecificationWorking01

Timestamp:

Dec 16, 2009, 10:15:15 AM (14 years ago)

Author:

pracine

Comment:

—

WKTRaster/SpecificationWorking01

@@ -165 +165 @@
 ----
 == '''Objective 0.1.6e - Being able to intersect vector and raster to produce vector.''' ==
- 
-'''ST_GetBBox(raster) -> polygon geometry'''
-
-List of similar functions in PostGIS:
-
-ST_Boundary(geometry) (not really - always return a geometry a dimension lower - i.e. the boundary of a polygon is a polyline.)[[BR]][[BR]]
-ST_box(geometry) (return a PostgreSQL box object)[[BR]][[BR]]
-ST_box2d(geometry) (return a box2d object)[[BR]][[BR]]
-ST_box3d(geometry) (return a box3d object)[[BR]][[BR]]
-ST_Envelope(geometry) Returns the minimum bounding box for the supplied geometry, as a geometry. The polygon is defined by the corner points of the bounding box ((MINX, MINY), (MINX, MAXY), (MAXX, MAXY), (MAXX, MINY), (MINX, MINY)). (PostGIS will add a ZMIN/ZMAX coordinate as well). In PostGIS, the bounding box of a geometry is represented internally using float4s instead of float8s that are used to store geometries. The bounding box coordinates are floored, guarenteeing that the geometry is contained entirely within its bounds. This has the advantage that a geometry's bounding box is half the size as the minimum bounding rectangle, which means significantly faster indexes and general performance. But it also means that the bounding box is NOT the same as the minimum bounding rectangle that bounds the geometry.[[BR]][[BR]]
-getBBOX(geometry) (Deprecation in 1.2.3)[[BR]]
-
-List of related functions in PostGIS:
-
-ST_extent(geometry set)[[BR]][[BR]]
-ST_ExteriorRing(geometry)[[BR]][[BR]]
+
+List of PostGIS functions similar or related to ST_GetBBox(), ST_Envelope(), ST_Shape():
+
+ST_Boundary(geometry) (not really - always return a geometry a dimension lower - i.e. the boundary of a polygon is a polyline.)
+
+ST_box(geometry) (return a PostgreSQL box object)
+
+ST_box2d(geometry) (return a box2d object)
+
+ST_box3d(geometry) (return a box3d object)
+
+getBBOX(geometry) (Deprecation in 1.2.3)
+
+ST_Envelope(geometry) Returns the minimum bounding box for the supplied geometry, as a geometry. The polygon is defined by the corner points of the bounding box ((MINX, MINY), (MINX, MAXY), (MAXX, MAXY), (MAXX, MINY), (MINX, MINY)). (PostGIS will add a ZMIN/ZMAX coordinate as well). In PostGIS, the bounding box of a geometry is represented internally using float4s instead of float8s that are used to store geometries. The bounding box coordinates are floored, guarenteeing that the geometry is contained entirely within its bounds. This has the advantage that a geometry's bounding box is half the size as the minimum bounding rectangle, which means significantly faster indexes and general performance. But it also means that the bounding box is NOT the same as the minimum bounding rectangle that bounds the geometry.
+
+envelope(geometry) (Deprecation in 1.2.3)
+
+ST_extent(geometry set)
+
+ST_ExteriorRing(geometry)
+
 ST_ConvexHull(geometry)
 
-
-'''ST_Envelope(raster|geometry) -> polygon geometry'''[[BR]]
-
-List of similar functions in PostGIS:
-
-ST_Boundary(geometry)[[BR]]
-ST_Envelope(geometry)[[BR]]
-envelope(geometry) (Deprecation in 1.2.3)[[BR]]
-ST_ExteriorRing(geometry)[[BR]]
-ST_ConvexHull(geometry)
-
-List of related functions in PostGIS:
-
-
-
-'''ST_Shape(raster) -> polygon geometry'''[[BR]]
-'''ST_AsPolygon(raster) -> polygon geometry set'''[[BR]]
-'''ST_Intersects(raster|geometry, raster|geometry)'''[[BR]]
-'''ST_Intersection(raster|geometry, raster|geometry, ‘raster’|’geometry’)->raster/geometry'''
+'''ST_GetBBox(raster) -> polygon geometry''' - Replaced with ST_Envelope() since there is no equivalent function in PostGIS.
+
+'''ST_Envelope(raster) -> polygon geometry''' Returns the minimum bounding box for the supplied raster, as a geometry. If the raser is rotated, the envelope is a non-rotated box enclosing the rotated raster.
+
+'''ST_Shape(raster) -> polygon geometry'''- Replaced with ST_ConvexHull(raster).
+
+'''ST_ConvexHull(raster) -> polygon geometry''' Returns the minimum convex geometry that encloses every pixel from the raster. 
+
+ By default the resulting polygon take the NODATA values into account and enclose only pixels having a value different than the NODATA value. The ST_ConvexHull(raster, 'WITHNODATA') variant do not take the NODATA value into account and generally return a square or rectangle polygon that can be rotated or not. If the raster is not rotated ST_ConvexHull(geometry, 'WITHNODATA') is equivalent to ST_Envelope(raster).
+
+'''ST_AsPolygon(raster) -> polygon geometry set''' Returns a 
+
+'''ST_Intersects(raster|geometry, raster|geometry)'''[[BR]][[BR]]
+'''ST_Intersection(raster|geometry, raster|geometry, ‘raster’|’geometry’)->raster/geometry'''[[BR]]
 
 ----