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

[Nicolas Ribot]

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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