Changes between Version 99 and Version 100 of WKTRaster/SpecificationWorking01

Timestamp:

Jan 5, 2010, 1:49:15 PM (14 years ago)

Author:

pracine

Comment:

—

WKTRaster/SpecificationWorking01

@@ -311 +311 @@
  Variant 2: ST_Intersects(raster, raster) -> boolean
 
- This function permform a full intersection test and proceed in two steps to determine if the raster intersects with the geometry:
-
- 1) First, it checks if the geometry returned by ST_ConvexHull(raster) intersects with the geometry.
-
- 2) If the first test returns TRUE, it checks if the geometry returned by ST_Shape(raster) intersects with the geometry. This test is slower since it involve the computation of the raster shape and it might involve the geometry shape.
+ This function permform a full intersection test and proceed in three steps to determine if the raster intersects with the geometry:
+
+ 1) First, it checks if the bounding box of the raster intersects with the bounding box of the geometry.
+
+ 2) If the first test returns TRUE, it checks if the geometry returned by ST_ConvexHull(raster) intersects with the geometry.
+
+ 3) If the second test returns TRUE, it checks if the geometry returned by ST_Shape(raster) intersects with the geometry. This test is slower since it involve the computation of the raster shape and it might involve the geometry shape.
 
  Variant 2 proceeds in a very similar way except that convex hulls of both rasters are computed and compared in step 2) and both shape of raster are computed and compared in step 3).