[mapguide-users] Raster re-projection pretest

[Andy Morsell]

I can't help much with your issue, but wanted to comment that the area I was
also testing in was Southeast Alaska.  I was reprojecting UTM Zone 8 images
to AK-1 (NAD27).  It's funny that you're working in the same relative area.

By the way, your attachments did not come through to the mailing list.  Try
posting a link to them instead.

Andy Morsell, P.E.
Spatial Integrators, Inc.
www.SpatialGIS.com

-----Original Message-----
From: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of Plantech
Sent: Monday, April 13, 2009 7:12 AM
To: mapguide-users at lists.osgeo.org
Subject: Re: [mapguide-users] Raster re-projection pretest


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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