[postgis-devel] [PostGIS] #866: [raster] Change the ST_MapAlgebra nodatavalueexpr text parameter for nodatavaluerepl
PostGIS
trac at osgeo.org
Sat Oct 1 06:36:12 PDT 2011
#866: [raster] Change the ST_MapAlgebra nodatavalueexpr text parameter for
nodatavaluerepl
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Reporter: pracine | Owner: dzwarg
Type: defect | Status: assigned
Priority: blocker | Milestone: PostGIS 2.0.0
Component: postgis raster | Version: trunk
Keywords: |
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Comment(by pracine):
Replying to [comment:4 dzwarg]:
> Is this ticket intended to only change the ''name'' of the parameter
from "nodatavalueexpr" to "nodatavaluerepl"?
>
> Or does this ticket also imply that the evaluation of the
"nodatavaluerepl" string will no longer occur, and that any text passed in
as this parameter gets converted to the raster cell data type and stored
as "newinitialvalue" in RASTER_mapAlgebra?
This is not just a parameter name change. The expression passed should
evaluate to a numeric value the same type of the resulting pixel type. I
guess the best bet for the type of this parameter is double precision even
if the requested resulting raster pixel type is int. Yes this value should
be used to initialize the raster in order to avoid (skipping) computing
values for nodata values.
I would change the script/plpgsql/st_mapalgebra.sql first.
Sorry for the late answer.
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Ticket URL: <https://trac.osgeo.org/postgis/ticket/866#comment:5>
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