[mapserver-dev] PostGIS "curvepolygon" support

[Paul Ramsey]

Astrid,

It would make sense to generally handle the curvey types in the run,
including the compoundcurve and circularstring as forms of mapserver
LINE types. I think your thread suggestion is correct (perhaps?) in
that it would be "simplest" to just paper over the curve types in the
postgis driver. This is in fact what is happening (sort of) in the
Oracle driver already.

The papering-over could take two forms.

(a) We could change the SQL being send to PostGIS to ensure that
curves are stroked (turned into equivalent linestrings) on the
database side.
(b) Or we could extract the stroking routines that have already been
written in the Oracle driver to a globally accessible area, genericize
them a little, and use them to stroke PostGIS curves in the MapServer
code.

The advantage of (b) is that the stroking routines would then be
generically available to any other driver that needs to stroke curves.
It would be a little more work than hacking up the SQL generated by
the PostGIS driver to get the server to do the work of stroking.

Does anyone else have interest in this issue?

Paul

On Mon, Nov 8, 2010 at 11:06 PM, Astrid Emde <astrid.emde at wheregroup.com> wrote:
> Hello devs,
>
> there was a discussion going on about PostGIS "curvepolygon" support for
> MapServer. At the moment polygons without curves are
> drawn, the ones with curves not.
>
> Here is the discussion link:
>
> http://osgeo-org.1803224.n2.nabble.com/PostGIS-curvepolygon-support-tt5372049.html
>
> One of our customers would like to sponsor this implementation and would
> like to know how much this enhancement would cost. It would be good if you
> could handle polygons and curevepolygons in one MapServer layer from TYPE
> POLYGON.
>
> In the thread there was also the discussion about a solution which is
> implemented in the PostGIS driver ...
>
>>  Curiously could this mean adding to the PostGIS driver a means of
>>  going from curve to shapeObj? As opposed to adding a curve shape
>>  type within MapServer.
>
> Could you please discuss a possible solution and estimate the costs? Who
> would be the contact person concerning this enhancement?
>
> Maybe there are other MapServer users interested in this enhancement and
> would also sponsor the implementation.
>
> --
>
> Best regards
> Astrid Emde
>
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