21 Jan 2009, 15:23
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Richard Bianchi (3 posts)

Gary,

First of all thank you for writing Desktop GIS. It is just the kind of book I was looking for and has been very helpful.

One open source desktop application which is curiously missing from the book is MapWindow GIS which can be found at http://www.mapwindow.org/.

I use Quantum GIS to plan and document my geocaching and hiking trips in various nearby Florida parks. The GIS department of local land management government agency makes available on their web site high-quality (as good as 6 inch per pixel!) imagery which is updated every year. This imagery is provided in MrSID format which seems to be fairly common.

Even though MapWindow GIS and QGIS both seem to make use of GDAL, which has the ability to read MrSID format files (at least it does in FWTools 2.2.8), MapWindow v4.6 is able to load SID files while QGIS v0.11 is not.

I don’t appear to be alone in my frustration in QGIS’s lack of support for MrSID format as is evidenced by this tread in the Quantum GIS Forum: http://forum.qgis.org/viewtopic.php?f=5&t=385

Is there some reason why support for this format continues to be left out of QGIS?

24 Jan 2009, 00:08
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Gary Sherman (7 posts)

The 1.0 release of QGIS (announced today) includes MrSID and ECW support on the Windows platform. For other platforms it is really a packaging/license issue that the QGIS developer team continues to consider.

27 Jan 2009, 05:33
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Richard Bianchi (3 posts)

I’ve installed QGIS 1.0.0-Kore using the OSGeo4W installer on my PC running Windows XP SP3 and I still get “not a supported raster data source” when I attempt to load a SID file. Am I doing something wrong?

28 Jan 2009, 03:00
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Gary Sherman (7 posts)

I have not used the Windows version (Mac and Linux are my primary platforms). Let me check into it…

28 Jan 2009, 04:08
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Gary Sherman (7 posts)

You have to do an “Advanced” install and choose the desktop and command line packages you want (eg. qgis), then choose gdal16-mrsid plugin from the Libs tree.

04 Feb 2009, 07:05
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Richard Bianchi (3 posts)

THANK YOU! At last I can add a MrSID raster layer! I had done the “Advanced” install, but I hadn’t noticed the gdal16-mrsid plugin in the Libs tree.

Oddly, when I load the SID raster layer, the Projection Selector pops up saying “This layer appears to have no projection specification” and prompts me to select one. The file contains this information, and after loading, it is even shown in the Metadata tab of the Raster Data Properties. But I can live with that.

I guess I need to set my Project Properties CRS to match the SID file projection (and enable ‘on the fly’ CRS transformation), load the raster layer, then load the vector layers (which are WGS 84).

P.S. Sorry for the delay in responding; I thought I had already posted this response last week (just before Firefox crashed).

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