Changes between Version 180 and Version 181 of WKTRaster/SpecificationWorking03

Timestamp:

11/29/11 14:18:07 (13 years ago)

Author:

pracine

Comment:

—

WKTRaster/SpecificationWorking03

@@ -529 +529 @@
  Following the conversion of geometry_columns to a view in PostGIS, it is planned to do the same with raster_column and raster_overview for the raster part. Converting to a view has a number of advantages:
 
+ * The raster_column view rows will always be in synch with the existing list raster columns
+ * All the information will be trustworthy because it will be enforced by constraints, so people can't change the band types etc... without changing the constraints. The raster_columns information will always be null (if the constraint does not apply) or correct.
+
  PostGIS is using the typmod feature of PostgreSQL to 'store' metadata about a table and then display them in the geometry_column view. Unfortunately the typmod is limited to XXX byte and there is too much information to 'store' about a raster table to use typmod. PostGIS raster will therefore use another approch consisting in 'store' metadata about a raster table as constraint on the table. A set of constraint will be applied to a raster table and those constraint will be read and displayed by the raster_column view.