[postgis-users] ST_Quantile

[Bborie Park]

Hey Joan,

Assuming your whole coverage is in a table, you should use the 
table/column version of ST_Quantile (which by the looks of it is 
undocumented for some reason).

The function definition of ST_Quantile(rastertable, rastercolumn) is...

st_quantile(rastertable text, rastercolumn text, nband int DEFAULT 1, 
exclude_nodata_value boolean DEFAULT TRUE, quantiles double precision[] 
DEFAULT NULL)

At the moment an aggregate version of ST_Quantile (and the other basic 
stats functions) does not exist.  It is expected that one will be 
written for PostGIS 2.1 assuming dev-time is available.

-bborie

On 01/27/2012 09:06 AM, Joan wrote:
> Hi,
>
> I would like to find the quantile values of a whole raster coverage, but
> ST_Quantile returns quantile values of each tile. Which would be the best
> method to approximate the quantile value of the whole coverage?
>
> Regards,
>
> Joan
>
>
>
>
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-- 
Bborie Park
Programmer
Center for Vectorborne Diseases
UC Davis
530-752-8380
bkpark at ucdavis.edu