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

[Nicolas Ribot]

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
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>>
>
>
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