[mapserver-dev] Server-side Simplication Speed-up

Smith, Michael ERDC-CRREL-NH Michael.Smith at usace.army.mil
Thu Mar 22 13:24:18 PDT 2012

I like this idea, it would be easier to add to each data driver.

Would you also make this a map file LAYER lever parameter so that it could
be controlled how much simplification would be desired? And perhaps a MAP
level one as well for a default.


On 3/22/12  4:19 PM, "Daniel Morissette" <dmorissette at mapgears.com> wrote:

>Could we add msLayerSetSimplifyResolution() that could be called to turn
>on/off the simplify stuff? Passing a valid resolution at the beginning
>of a rendering pass would enable it, and a resolution of 0 in other
>cases would disable it and return the original coordinates.
>On 12-03-22 3:59 PM, Paul Ramsey wrote:
>> Sandro working on MapNik says that this change
>> https://github.com/mapnik/mapnik/issues/1136
>> running an "appropriate" st_simplify on the geometries before sending
>> them over the wire to the renderer, gave up to 75% speedups on
>> rendering complicated items.
>> In order to try it out on MapServer, the PostGIS driver needs to know
>> two things:
>> - what's the resolution being rendered to? this I can pick up out of
>> the mapObj easily I think, tracing back up from the layerObj passed
>> into the driver
>> - is this a rendering call to the driver, or a feature access call?
>> this is harder... I need to distinguish between calls to the driver
>> that are going to use the features for rendering and those that are
>> going to send them back to the requester as data. Is there an obvious
>> global way to figure this out from the driver level?
>> P.
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>Daniel Morissette
>Provider of Professional MapServer Support since 2000
>mapserver-dev mailing list
>mapserver-dev at lists.osgeo.org

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