[postgis-tickets] [PostGIS] #2603: [raster] Add docs for ST_MapAlgebra with mask parameter

[PostGIS]

#2603: [raster] Add docs for ST_MapAlgebra with mask parameter
------------------------+---------------------------
  Reporter:  dustymugs  |      Owner:  dustymugs
      Type:  task       |     Status:  new
  Priority:  critical   |  Milestone:  PostGIS 2.2.0
 Component:  raster     |    Version:  trunk
Resolution:             |   Keywords:
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Comment (by robe):

 Ah okay I think I'm getting it now.  I kept on thinking it was being
 applied after the mapalgebra call. So should the mask always be 0s and 1s?
 I'm not sure that behavior works right because when I gave it a 5x5 matrix
 it complained dimension was not the same as neighbor (that's why I
 augmented the error message to see what it thought was wrong).  That's
 what I had thought that the distance was inferred from the matrix.

 Here is an example:


 {{{
 DROP TABLE IF EXISTS shapes;
 CREATE TABLE shapes(rid integer, rast raster);

 INSERT INTO shapes(rid,rast)
 VALUES ( 1, ST_AsRaster(
                 ST_Buffer(
                         ST_GeomFromText('LINESTRING(50 50,150 150,150
 50)'), 10,'join=bevel'),
                         200,200,ARRAY['8BUI'], ARRAY[118], ARRAY[0]) );

  SELECT st_mapalgebra(rast,1,'st_mean4ma(double precision[], int[],
 text[])'::regprocedure,'{{1,0,1,1,1}, {1,0,1,1,1}, {1,0,1,1,1},
 {1,0,1,1,1}, {1,0,1,1,1}}'::double precision[],false)
 FROM shapes;
 }}}


 Gives me:


 {{{
 ERROR:  rt_pixel_set_array: mask dimensions 5 x 5 do not match given dims
 3 x 3
 }}}


 Why doesn't the distancex/y become 2,2?

--
Ticket URL: <https://trac.osgeo.org/postgis/ticket/2603#comment:10>
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