[postgis-users] Creating a multiband raster from 3 single bandrasters

[Bborie Park]

Oops! Use Regina's link instead. I need to flush out my browser's history...

-bborie


On Sun, Jul 7, 2013 at 10:50 PM, Paragon Corporation <lr at pcorp.us> wrote:

> **
> cough cough: New docs
>
> http://postgis.net/docs/manual-dev/RT_ST_AddBand.html
>
> -Regina
>
>
>  ------------------------------
> *From:* postgis-users-bounces at lists.osgeo.org [mailto:
> postgis-users-bounces at lists.osgeo.org] *On Behalf Of *Bborie Park
> *Sent:* Monday, July 08, 2013 12:38 AM
> *To:* PostGIS Users Discussion
> *Subject:* Re: [postgis-users] Creating a multiband raster from 3 single
> bandrasters
>
>  Check out the last example (Multi-band versions) of ST_AddBand().
>
> http://postgis.refractions.net/documentation/manual-svn/RT_ST_AddBand.html
>
> -bborie
>
>
> On Sun, Jul 7, 2013 at 8:43 PM, Mark Wynter <mark at dimensionaledge.com>wrote:
>
>> I'm hoping someone can suggest a way of efficiently combining 3
>> individual (but concordant) single band rasters into single raster having 3
>> bands?  We're working with PostgreSQL9.1, PostGIS2.1Beta.
>>
>> The starting point is a single tiled raster with 3 bands representing RGB
>> values.
>>
>> Let's say we perform some color smoothing on each of the RGB bands using
>> mapalgebra.
>>
>> CREATE TABLE resample_myrastertable_b1 AS
>> SELECT rid, st_mapalgebrafctngb(rast, 1, '8BUI', 5, 5,
>> 'st_mean4ma(float[][],text,text[])'::regprocedure, 'ignore', NULL) as rast
>> FROM original_rastertable;
>>
>> CREATE TABLE resample_myrastertable_b2 AS
>> SELECT rid, st_mapalgebrafctngb(rast, 2, '8BUI', 5, 5,
>> 'st_mean4ma(float[][],text,text[])'::regprocedure, 'ignore', NULL) as rast
>> FROM original_rastertable;
>>
>> CREATE TABLE resample_myrastertable_b3 AS
>> SELECT rid, st_mapalgebrafctngb(rast, 3, '8BUI', 5, 5,
>> 'st_mean4ma(float[][],text,text[])'::regprocedure, 'ignore', NULL) as rast
>> FROM original_rastertable;
>>
>> This gives us 3 single-band results rasters.
>>
>> How do we now join the individual smoothed RGB "results" rasters into a
>> single multiband "results" raster?   We'd also like to add a 4th band to
>> the "results" raster based on say a calculation which references the
>> smoothed values in bands 1-3.
>>
>> I'm getting reasonably comfortable writing MapAlgebra callback
>> expressions.   Its more a case of how do we efficiently handle table
>> operations (e.g. appending single band raster outputs) each time we perform
>> some MapAlgebra?
>>
>> Any suggestions and or a simple worked example would be most appreciated.
>>
>> Many thanks
>>
>> Mark
>>
>>
>>
>>
>> _______________________________________________
>> postgis-users mailing list
>> postgis-users at lists.osgeo.org
>> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users
>>
>
>
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