[mapguide-users] Raster re-projection pretest

[Plantech]

I also have tried the raster on the fly reprojection within the MGE 2010 environment.  While it works as you note I noticed a problem with perhaps certain projections.  On a project in Alaska, I have my source ECW aerial files in AK83-1F, Alaska State Plane.  My map coordinate system is Alaska NAD27 Albers Equal Area.  From a view where the aerial is completely within the display with about 25% white space outside of the borders, the complete aerial displays properly.  However, if I zoom in past the borders of the aerial, I start getting truncating of strips of the aerial along each side, leaving white space.  These appear related to the rotation of the reprojection.  If I use LL83 for my base coordiate system, I don't seem to have the problem.  There also not as much rotation on this reprojection.  I have attached screenshots of this comparison.

Realizing that MGE 2010 is just out, has anybody else seen this?  Would this be common with MGOS?

Jer


I wanted to provide some positive feedback to the group about a particular
feature that I've been looking forward to.  I just installed the release
version of MapGuide Enterprise 2010.  It includes some features not in the
current release of MGOS, but those features will be in the upcoming release
(2.1) which is due next week.  RFC 51
(http://trac.osgeo.org/mapguide/wiki/MapGuideRfc51) provides support for
raster re-projection.  Meaning, you can leave rasters images in their native
coordinate system and it will re-project them to the map coordinate system
on the fly.  I just quickly tested it with a couple of 100 MB TIF's that are
in UTM while my map was in a State Plane coordinate system.  It worked.  It
wasn't very fast, but it worked.  I then converted the images to my
preferred format of ECW (both about 70 MB) and it was screaming fast with
the re-projection.  I'm talking less than a second response time.  Holy cow.
And, it correctly saw the null background values and ignored them so the
resulting mosaic of the two images looked great.  I'm impressed.  Hats off
to the developers for this feature.
 
(quick disclaimer: this test was done with the Autodesk Raster Provider.  I
assume it will work as well with the GDAL Raster Provider)
 
Andy Morsell, P.E.
Spatial Integrators, Inc.
www.SpatialGIS.com
 

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MGE2010_Reprojection.jpg 
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