[postgis-users] DISTINCT geometry to a code

[juli g. pausas]

Thanks Lars and Nicolas,
The windows option is simple and do exactly what I wanted. thanks.

Juli
--
*CIDE, CSIC*  |  www.uv.es/jgpausas  |  blog <http://jgpausas.blogs.uv.es/>


On Wed, Mar 15, 2017 at 5:42 PM, Nicolas Ribot <nicolas.ribot at gmail.com>
wrote:

> Hi,
>
> You could use a windows function to generate ids for the points:
>
> SELECT  geom, row_number() over () as code
> FROM juli.savannaswdsp
> group by geom;
>
> Nicolas
>
> On 15 March 2017 at 15:49, juli g. pausas <juli.g.pausas at uv.es> wrote:
>
>> Hi
>> I have a table with 945361 rows but the geometry (points) are distinct
>> for 201606 locations (i.e., some rows refer to the same point in the space).
>>
>> SELECT count(*) FROM juli.savannaswdsp;                           --
>> 945361
>> SELECT  count(DISTINCT geom) FROM juli.savannaswdsp;   -- 201606
>>
>> Would it be possible to generate a column with codes for the points? that
>> is, like an ID for each point instead for each row (e.g., from 1 to
>> 201606), so rows with the same geom have the same code.
>>
>> [ In R language this would be as follows: as.numeric(as.factor(geom))  ]
>>
>> Thank for any suggestion
>>
>> Juli
>> --
>> *CIDE, CSIC*  |  www.uv.es/jgpausas  |  blog
>> <http://jgpausas.blogs.uv.es/>
>>
>>
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>
>
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