Changes between Version 159 and Version 160 of WKTRaster/SpecificationWorking03

Timestamp:

Oct 5, 2011, 4:15:48 PM (13 years ago)

Author:

Bborie Park

Comment:

—

WKTRaster/SpecificationWorking03

@@ -194 +194 @@
  See discussion in http://trac.osgeo.org/postgis/ticket/590
 
-'''ST_SameAlignment(raster, raster) -> boolean'''
-
- This function returns true if both rasters' grids are aligned.
-
- Two rasters grid are aligned if:
-
-  -They share the same pixel scales and skews
-
-  -At least one of any of the four corner of any pixel of one raster fall on any corner of the grid of the other raster.
-
- Alignment is not the same concept as georeference. Two rasters can be aligned but not have the same georeference.
-
- Rotation is important here since two rasters grid might look perfectly aligned but are not if their rotated are different.
-
- Knowing if two rasters share the same alignment is useful when it is time to decide if one of them must be resampled before doing other operations (like ST_MapAlgebra on two rasters).
-
- '''Variants'''
-
-  1) ST_SameAlignment(ulx1, uly1, scalex1, scaley1, skewx1, skewy1, ulx2, uly2, scalex2, scaley2, skewx2, skewy2)
-
-  2) ST_SameAlignment(rast1 raster, rast2 raster)
-
- The first variant is useful to PL/pgSQL function which have already get the values of the parameters.
-
- '''Implementation Details'''
-
- Only the first variant should be implemented in C. The second one is a PL/pgSQL variants. The C implementation should follow the PL/pgSQL version implemented in http://trac.osgeo.org/postgis/browser/trunk/raster/scripts/plpgsql/st_mapalgebra.sql
-
- It is not clear if this PL/pgSQL implementation works when raster are rotated. To verify.
-
- See discussion in http://trac.osgeo.org/postgis/ticket/589
-
-Bborie:
-
-The variant that should be developed in C is (2) as it is more likely that someone will have two rasters instead of that large set of raster elements.  Instead, (1) should be a pl/pgsql function calling (2).
+'''ST_SameAlignment(raster, raster) -> boolean - done see below'''
 
 ----
@@ -2910 +2876 @@
 
 ----
+== '''Objective FV.03 - Implement all the necessary versions of ST_MapAlgebra''' ==
+
+'''ST_SameAlignment(raster, raster) -> boolean'''
+
+This function returns true if both rasters' grids are aligned.
+
+Two rasters grid are aligned if:
+
+* They share the same pixel scales and skews
+
+* At least one of any of the four corner of any pixel of one raster fall on any corner of the grid of the other raster.
+
+Alignment is not the same concept as georeference. Two rasters can be aligned but not have the same georeference.
+
+Rotation is important here since two rasters grid might look perfectly aligned but are not if their rotated are different.
+
+Knowing if two rasters share the same alignment is useful when it is time to decide if one of them must be resampled before doing other operations (like ST_MapAlgebra on two rasters).
+
+The variants of ST_SameAlignment are:
+
+1. ST_SameAlignment(rast1 raster, rast2 raster)
+
+2. ST_SameAlignment(ulx1, uly1, scalex1, scaley1, skewx1, skewy1, ulx2, uly2, scalex2, scaley2, skewx2, skewy2)
+
+~~The first variant is useful to PL/pgSQL function which have already get the values of the parameters.
+
+~~'''Implementation Details'''
+
+~~Only the first variant should be implemented in C. The second one is a PL/pgSQL variants. The C implementation should follow the PL/pgSQL version implemented in http://trac.osgeo.org/postgis/browser/trunk/raster/scripts/plpgsql/st_mapalgebra.sql
+
+~~It is not clear if this PL/pgSQL implementation works when raster are rotated. To verify.
+
+~~See discussion in http://trac.osgeo.org/postgis/ticket/589
+
+~~Bborie:
+
+~~The variant that should be developed in C is (2) as it is more likely that someone will have two rasters instead of that large set of raster ~~elements.  Instead, (1) should be a pl/pgsql function calling (2).
+
+----
 == '''Objective FV.05 - Being able to reproject a raster. - ''Done''''' ==