[mapguide-users] Two Raster Display Questions (Stretching andRemoving Collars)

[Andy Morsell]

Darren,
Image transparency is a function of the GDAL provider and it is not
supported for images other than PNG as discovered by other users.  I, for
one, hope to see this become a standard feature of both the GDAL and
Autodesk Raster providers for non-bitonal images since it is a very common
need for GIS applications.  The only work-arounds are to convert to PNG, as
mentioned, or mosaic your images together while having the mosaicing
application ignore the null (transparent) pixels and then convert the mosaic
to a compressed format (ecw, MrSID, jpg2000) or to tile the mosaic into
smaller sub-images.

Andy Morsell, P.E.
Spatial Integrators, Inc.
47° 46' N 116° 49' W
www.SpatialGIS.com


-----Original Message-----
From: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of Darren Cope
Sent: Tuesday, September 08, 2009 6:20 PM
To: mapguide-users at lists.osgeo.org
Subject: RE: [mapguide-users] Two Raster Display Questions (Stretching
andRemoving Collars)


Hi Mark,

Sorry, upon re-reading my post I realize it was a bit unclear.  The images
are not in fact bitonal. I only mentioned that I had tried the bitonal
setting to show that I had tried everything I can think of!  However, my
interpretation of the "Transparency Colour" setting under Advanced in
Maestro was that it would perform a similar function for images that were
not bitonal.  Perhaps I'm wrong in this interpretation?

Cheers,

Darren


Nichols, Mark A. wrote:
>
> Regarding your question about bitonal images.  Yes, I've got them to work.
>
> See this previous post:
> http://n2.nabble.com/Bitonal-Image-Problem-td3156619.html
>
> It might take some work in Irfanview to get just the right export as png.
>
> Mark
>
>
> -----Original Message-----
> From: mapguide-users-bounces at lists.osgeo.org on behalf of Darren Cope
> Sent: Tue 9/8/2009 7:40 AM
> To: mapguide-users at lists.osgeo.org
> Subject: Re: [mapguide-users] Two Raster Display Questions (Stretching
> andRemoving Collars)
>
>
> I'm still struggling after having tried everything I can think of.  Is the
> only solution to pre-process the imagery via gdal or the like?  If so,
> which
> command would I use to 'stretch' the histograms without actually modifying
> the pixel (elevation) values in the DEMs?
>
> Any thoughts on either question much appreciated.
>
> Cheers,
>
> Darren
>
>
> Darren Cope wrote:
>>
>> Hi folks,
>>
>> Two questions regarding raster display in MGOS:
>>
>> 1.  I have a set of DEMs from Geobase (approx. 100 tiles).  I've created
>> a
>> Data Connection in Studio to the directory containing the images, and
>> then
>> a layer pointed at the data connection.  However, because the max/min
>> values of each tile differ, they are not displayed using the same range.
>> How can I 'stretch' all tiles to the max/min of the entire set?  Images
>> are in GeoTiff format if that matters.
>>
>> 2.  I have a set of SPOT imagery (also from GeoBase) that are set up in
>> the same way as above (except in ecw format).  How do I remove the black
>> collars around the images?  The Bitonal Image settings in Studio don't
>> seem to work, and the "Transparency Colour" under Advanced in Maestro
>> doesn't work either.  Thoughts?
>>
>> Thanks for your help!
>>
>
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