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<div class="gmail_quote">On Mon, Nov 10, 2008 at 10:22 AM, Hamish <span dir="ltr"><<a href="mailto:hamish_b@yahoo.com">hamish_b@yahoo.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Matt:<br>
<div class="Ih2E3d">> > At the moment I'm trying to georectify a stitched<br>> > together google earth image<br><br></div>often r.in.wms / r.in.onearth is just as good and totally free.<br>(r.in.onearth from wiki addons)<br>
<div class="Ih2E3d"><br>> > I've imported the raster into grass using gdal, it<br>> > splits it up into 3 (RGB) files? and I can display it (in<br>> > the wrong place at the wrong scale). I also have the<br>
> > coordinates of the 4 corner points of the image and those<br>> > are what I'm using to georeference using the<br>> > georeferencing tool from the file menu.<br><br></div>in that case, avoid all the hassle and just use r.region.<br>
<br><br>Moritz:<br>
<div class="Ih2E3d">> In which location are you running the georeferencing tool ?<br>> You have to run it in the target location, not in the<br>> location where you imported your original images.<br>><br>> Workflow:<br>
><br>> - create two locations, one XY (unprojected) and one<br>> projected in the reference system you want to georeference<br>> the images into (AFAIR, Google Earth uses WGS84 lat-long,<br>> alias EPSG code 4326<br>
> - import images with r.in.gdal into the XY location<br>> - in the projected location, run georectifying tool<br><br><br></div>wiki FAQ entry:<br><br> <a href="http://grass.osgeo.org/wiki/Georeferencing" target="_blank">http://grass.osgeo.org/wiki/Georeferencing</a><br>
<font color="#888888"><br><br>Hamish<br></font></blockquote></div>
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<div>Thanks Hamish & Moritz,</div>
<div> I'm using this to figure out how to georeference. The tutorials / wiki are useful but for someone new to GRASS there is a little detail lacking in the documentation. I think my problem at the moment is that I've got a theoretical understanding of how groups and locations work but applying this to the menu structure/workflow within grass is another thing.</div>
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<div>Locations: basically a place in the grass database with an area (ie region) and a projection. Data within the location is stored in groups. ie, one raster split into RGB would be a group, an imported shapefile or possibly set of shapefiles would be another group.</div>
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<div>Locations need to be created when starting grass.</div>
<div>Do I need to have a group created before I import data or, is there a group created when I import data? I can import vector data easily enough and I'm not prompted to create a group usually, however I am having trouble creating a group using the i.group tool. If I start it form within the georectify tool it won't accept any input until I close the georectify window and it usually crashes. The man page doesn't have a cli example on how to create a group within the location (that I can remember, I'm away from my grass pc today).</div>
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<div>Thanks</div>
<div>Matt</div>
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