[mapguide-users] Polygon labels - fusion problems

[Traian Stanev]

If you are using RenderMap (note that this is the server API call, not sure what the web API name is) to make tiles which are supposed to align, then you want clipping to be off -- otherwise you are guaranteed to have overlapping and cut off labels on every tile boundary. That's the only problem I can think of that would require RenderMap to not clip polygons for the purpose of labeling.

Traian


> -----Original Message-----
> From: mapguide-users-bounces at lists.osgeo.org [mailto:mapguide-users-
> bounces at lists.osgeo.org] On Behalf Of Paul Spencer
> Sent: Monday, February 18, 2008 11:04 AM
> To: MapGuide Users Mail List
> Subject: Re: [mapguide-users] Polygon labels - fusion problems
>
> Traian,
>
> my understanding was that I should be using GetMapImage for drawing
> the map and GetVisibleMapExtent/GetDynamicMapOverlay for the
> selection.  And in fact, I think Trevor modified GetDynamicMapOverlay
> to allow rendering just the selection.
>
>  From what you said below, it now appears that I should be using
> GetVisibleMapExtent/GetDynamicMapOverlay for rendering map draws.
>
> Note that this is problematic for OpenLayers because it currently uses
> a synchronous AJAX call to GetVisibleMapExtent which is not desirable
> and will require a rework of the MapGuide support in OpenLayers to
> allow this to be done asynchronously.
>
> Is there any reason why the two operations would be implemented
> differently?  Is one more correct than the other?
>
> Cheers
>
> Paul
>
> On 15-Feb-08, at 6:20 PM, Jason Birch wrote:
>
> > Traian, Paul,
> >
> > I observed considerable performance degradation between the old
> > version
> > of Fusion (pre-MGOS) that used GetDynamicMapOverlay instead of
> GetMap.
> > This was with my Cemetery map data that has the nasty buffered roads
> > layer.  Sheboygan seemed to be fairly quick regardless.
> >
> > I'm wondering if this difference (clipping off) could be the
> > culprit?  I
> > don't see the same performance decrease in the AJAX viewer for this
> > map.
> >
> > I discussed this with Paul earlier, and think I was supposed to
> > submit a
> > bug report, but wasn't able to quickly put together a reproducible
> > error
> > report and it slipped my mind (doh!).
> >
> > Jason
> >
> >
> > -----Original Message-----
> > From: Traian Stanev
> > Subject: RE: [mapguide-users] Polygon labels - fusion problems
> >
> >
> > I think it could be that Fusion uses a RenderMap API which uses
> > viewport
> > clipping turned off (resulting in labels always being at the true
> > centroid of polygons) while the MG ajax viewer uses
> > RenderDynamicOverlay, which has viewport clipping turned on,
> resulting
> > in polygons being labeled at the centroid of the clipped region.
> > _______________________________________________
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> > mapguide-users at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/mapguide-users
>
> --
> Paul Spencer
> CTO, DM Solutions Group Inc
> http://www.dmsolutions.ca/
>
>
>
>
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