[postgis-users] ST_SimplifyPreserveTopology and ST_Simplify does not preserve measures

[Nicolas Ribot]

By the way, wich Pgis version ?

On  POSTGIS="2.0.2 r10789" , it gives correct result:

select st_astext(st_simplify('LINESTRINGM(0 0 0, 1 1 1, 10 10
10)'::geometry, 1));
           st_astext
-------------------------------
 LINESTRING M (0 0 0,10 10 10)
(1 row)

Nicolas


On 7 February 2013 16:33, Nicolas Ribot <nicolas.ribot at gmail.com> wrote:

> Sorry, answered to fast... ;)
> Don't know with it drops M dimension.
>
>
> On 7 February 2013 16:28, Nicolas Ribot <nicolas.ribot at gmail.com> wrote:
>
>> Hi,
>>
>> You are simplifying data with a 1000 degrees tolerance !
>> Project your data into a planar system, then simplify it.
>>
>> Nicolas
>>
>>
>> On 7 February 2013 15:59, Egil Möller <egil at skytruth.org> wrote:
>>
>>> It seems like ST_SimplifyPreserveTopology and ST_Simplify does not
>>> preserve measure coordinates and mangles my linestringm to an ordinary
>>> linestring. Why is that? It seems like a rather random limitation!
>>>
>>> mydb=> select ST_AsEWKT(line) from ais_path limit 1;
>>>  SRID=4326;LINESTRINGM(102.647916667 5.63022166667
>>> 1357100014,102.647916667 5.63022166667 1357446366)
>>>
>>> mydb=> select ST_AsEWKT(ST_SimplifyPreserveTopology(line, 1000)) from
>>> ais_path limit 1;
>>>  SRID=4326;LINESTRING(102.647916667 5.63022166667,102.647916667
>>> 5.63022166667)
>>>
>>> Best regards,
>>> Egil
>>> _______________________________________________
>>> postgis-users mailing list
>>> postgis-users at lists.osgeo.org
>>> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users
>>>
>>
>>
>
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