[postgis-devel] Regular expressions in PostGIS sources

[Paul Ramsey]

2010/11/15 Jorge Arévalo <jorge.arevalo at deimos-space.com>:

> Just now we have a PL/pgSQL implementation of MapAlgebra, that uses
> 'replace' string function to replace the word 'rast' for a given value
> in expressions like 'select rast + 20' and then run EXECUTE expr
> INTO... statement

If you can get valid results from straight SQL why not drop the whole
ST_MapAlgebra function and just define your semantics in terms of SQL
operators and overloaded functions (eg sqrt(raster)), documenting how
to "do MapAlgebra" using SQL commands?

P.