[postgis-devel] [PostGIS] #588: [raster] Implement the one raster version of ST_MapAlgebra

[Pierre Racine]

I did not have time to test it yet. How fast is it?

>-----Original Message-----
>From: PostGIS [mailto:trac at osgeo.org]
>Sent: 17 février 2011 07:44
>Cc: postgis-devel at postgis.refractions.net
>Subject: Re: [PostGIS] #588: [raster] Implement the one raster version of ST_MapAlgebra
>
>#588: [raster] Implement the one raster version of ST_MapAlgebra
>-----------------------------+----------------------------------------------
>  Reporter:  pracine         |       Owner:  jorgearevalo
>      Type:  task            |      Status:  closed
>  Priority:  medium          |   Milestone:  PostGIS 2.0.0
> Component:  postgis raster  |     Version:  trunk
>Resolution:  fixed           |    Keywords:
>-----------------------------+----------------------------------------------
>
>Comment(by robe):
>
> That's the weird thing - everything was going good and then suddenly I
> would get errors like SELECT CASE WHEN mod(200.00,2)  ... rast  (RAST does
> not exist) errors.
>
> Though I can't trip it up now with a case:  These work fine for example,
> but it wasn't the one I was testing yesterday (which is why I thought it
> was one of those heisenburgs).
>
> However I do keep on getting a notice that my initial value is truncated
> when I do things like this:
>
> ALTER TABLE dummy_rast ADD COLUMN map_rast raster;
> UPDATE dummy_rast
>   SET map_rast = st_mapalgebra(rast, 'CASE WHEN mod(rast,2) = 1 THEN rast
> WHEN rast = 254 THEN 100 WHEN rast < 253 THEN mod(rast,4) ELSE rast END')
> WHERE rid = 2;
>
> Is that one of those weird windows bugs?
>
> Gives warning:
>
>
> {{{
> WARNING:  Initial pixel value for 8BUI band got truncated from -128.000000
> to 128
> }}}
>
>
> But result above looks right.
>
>
> I think the other case with the PixelType not working was user error on my
> part.  I had typed 2BB instead of 1BB or 2BUI.  I didn't get a warning
> message or error, but it didn't convert the pixeltype -- it left it as
> 8BUI.  I think maybe we should throw an error if someone types in an
> invalid PixelType -- you know just for people like me :).  It wouldn't be
> pleasant if you thought that you had a 2BB pixel band and 1 million
> updates later, you realized it was really 8 BUI.
>
>--
>Ticket URL: <https://trac.osgeo.org/postgis/ticket/588#comment:7>
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