[postgis-devel] ST_MapAlgebraExpr(): Raster aggregates?

[Bborie Park]

On Fri, Nov 18, 2011 at 3:24 AM, Tom van Tilburg
<tom.van.tilburg at gmail.com> wrote:
> Hi list,
>
> At the moment I'm looking at the option of turning vector maps with discrete
> (non overlapping)  data into rasters with the help of the WKTraster
> functionality.
> At the moment I do as follows:
> 1. Collect (aggregate) al geoms from the same class
> 2. Make the into a raster with St_AsRaster()
> 3. Repeat for all classes
> 4. Merge all resulting rasters into 1 with ST_MapAlgebraExp()
>
> This step 4 I have to repeat (nest) a lot of times (for every class I have
> in my vector data). It would be great to have St_MapAlgebraExp() as an
>  aggregate function instead of just 2 rasters. This would greatly simplify
> the process of turning land use data from vectors/topology into raster. Is
> there any such thing available or in the make?
>
> Regards,
>  Tom

Hey Tom,

Currently, an aggregate version isn't available.  It is planned on
being developed but there currently isn't any dev time available to
actually write it.  I do plan on writing it though as I need it for my
work.

-bborie