[Qgis-developer] Postgresql provider - Use ST_RemoveRepeatedPoints for server-side simplification

[kimaidou]

Hi all,

I updated my PR.
I made some quick tests, and it seems this PR can improve speed for PostGIS
layers ( with PostGIS 2.2 )
More details in the last comment [1]

Please help to test it with a variety of data types and complexity.

[1] https://github.com/qgis/QGIS/pull/2410#issuecomment-160138487

Regards
Michaël aka "kimaidou"

2015-10-30 11:50 GMT+01:00 kimaidou <kimaidou at gmail.com>:

> Hi all
>
> Following the blog post written by Paul Ramsey [1], I decided to propose
> using PostGIS 2.2 ST_RemoveRepeatedPoints function instead of ST_SnapToGrid
> to do the server side simplification
>
> We could also investigate other new features, such as the 3rd parameter
> for ST_Simplify, but we use St_SimplifyPreserveTopology in QGIS, and I do
> not think this function has got this new parameter too.
>
> I made a pull request : see [2]
> Please help me to test and review it
>
> [1] http://blog.cartodb.com/smaller-faster/
> [2] https://github.com/qgis/QGIS/pull/2410
>
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