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<TITLE>new GRASS georectifier for rasters and vectors</TITLE>
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<FONT FACE="Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12.0px'>I’ve finished the new GRASS georectifier for the GIS Manager and committed it to the cvs. <BR>
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It is pure TclTk for all graphics, with wrappers for the GRASS modules i.group, i.target, i.rectify, v.transform, and g.transform. So it doesn’t use or need x11.<BR>
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Start out in the location/mapset you want to georectify INTO.<BR>
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It is a comprehensive tool to georectify raster and vector maps. It will allow you to graphically click on a reference unrectified map (raster or vector) and a rectified map (of any kind) to create ground control points (GCP’s). You can also type them in by hand if you want, with full editing of any GCP and the option of having it used or not used in the final rectification. <BR>
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It creates a group organization for vectors (using a file of VREF instead of REF) that parallels that created by i.group. So now any group can have a REF file of rasters and a VREF file of vectors to be georectified, using the same POINTS file. Or you can have separate groups for rasters and vectors. Your choice. Like i.rectify, it will batch rectify a group of vectors (e.g., layers from a DXF file). <BR>
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Currently, i.rectify and v.transform work quite differently. It would be nice if both could read the same kind of files, use a similar group structure, and work like v.proj/r.proj in rectifying INTO the working location/mapset. So there there is considerable coding to make them appear to work alike and have a consistent interface throughout the georectifier.<BR>
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It will also calculate forward and back projected error for each GCP and forward and backward RMS error for the group. Please give it a try and let me know what you think. Because it’s small, I’ve attached a copy here to save you the trouble of downloading. You can just drop it into your $GISBASE/etc/gm folder.<BR>
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Thanks very much to Glynn Clements, who offered advice and created g.transform to calcuate GCP errors.<BR>
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Michael<BR>
__________________________________________<BR>
Michael Barton, Professor of Anthropology<BR>
School of Human Evolution & Social Change <BR>
Center for Social Dynamics and Complexity<BR>
Arizona State University<BR>
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phone: 480-965-6213<BR>
fax: 480-965-7671<BR>
www: <a href="http://www.public.asu.edu/~cmbarton">http://www.public.asu.edu/~cmbarton</a> <BR>
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