[postgis-users] ST_Quantile

[Joan]

Hi Bborie,

This is my query and it crashes the db server.
select st_quantile('kbd_ext', 'rast', 0.75) from kbd_ext limit 10;

Joan

On 27 January 2012 19:14, Bborie Park <bkpark at ucdavis.edu> wrote:

> 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
>>
>>
>>
>>
>> ______________________________**_________________
>> postgis-users mailing list
>> postgis-users at postgis.**refractions.net<postgis-users at postgis.refractions.net>
>> http://postgis.refractions.**net/mailman/listinfo/postgis-**users<http://postgis.refractions.net/mailman/listinfo/postgis-users>
>>
>
> --
> Bborie Park
> Programmer
> Center for Vectorborne Diseases
> UC Davis
> 530-752-8380
> bkpark at ucdavis.edu
>
> ______________________________**_________________
> postgis-users mailing list
> postgis-users at postgis.**refractions.net<postgis-users at postgis.refractions.net>
> http://postgis.refractions.**net/mailman/listinfo/postgis-**users<http://postgis.refractions.net/mailman/listinfo/postgis-users>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/postgis-users/attachments/20120127/16e0301f/attachment.html>