[Qgis-developer] Enhanced georeferencer plugin

[Maxim Dubinin]

Dear Jukka,

this functionality is already implemented in new Georeferencer plugin.
You can grab a copy for Ubuntu from svn mentioned here [1] or wait for new 1.0.1 (?) release
of QGIS, where it will be part of standard distribution.

http://gis-lab.info/qa/qgis-georef-new-eng.html

Meanwhile, we'll be glad to hear from you regarding any problems with
this plugin.

-- 
Best regards,
 Maxim                          mailto:sim at gis-lab.info

Вы писали 4 февраля 2009 г., 7:07:52:

RJ> Hi,
RJ> This message has been lying for some days in QGis forum and now I
RJ> was adviced to send it to mailing list.
RJ> -Jukka Rahkonen-
RJ>  
RJ> Forum message follows:
RJ> "The Georeferencer plugin is pretty nice to use. However, I have
RJ> found that the result of georeferencing with world file is not
RJ> always satisfactory. Therefore I have used the fine user interface
RJ> for collecting ground control points and done the rest of
RJ> georecerencing with other tools. However, I believe that it should
RJ> be rather easy to modify the Georeferencer plugin so that it could
RJ> do georeferncing also with this alternative way. As a result QGis
RJ> would have a georeferencing tool of professional quality both when
RJ> it comes to easy of use and accuracy.
RJ> The work flow would be like this:
RJ> 1. Ground control points are collected with the existing plugin.
RJ> It is gathering all the information that is needed for the next
RJ> step (mapX, mapY, pixelX, pixelY)
RJ> 2. Ground control points are fed for gdal_translate program as
RJ> -gcp parameters. Gdal_translate takes them in this order:
RJ> [-gcp pixel line easting northing [elevation]]*
RJ> The whole gdal_translate command line would be
RJ> gdal_translate -of GTiff -gcp [params_1] -gcp [params_2] -gcp
RJ> [params_3] .... input.tif temporary.tif
RJ> 3. Third step is to warp the temparary image that contains now
RJ> the ground control points. It is done with gdalwarp, for example like this:
RJ> gdalwarp -of GTiff -s_srs epsg:4326 -t_srs epsg:4326 temporaty.tif warped.tif
RJ> Command lines are presented as working examples which can be
RJ> repeated with gdal utility programs. For the plugin it would be
RJ> better to call gdal funtions directly, use virtual raster format
RJ> as temporary format instead of tiff etc. I cannot say very much
RJ> about how it should be done because I can't program myself.
RJ> However, in the very end of this link
RJ> http://www.scangis.org/scangis2007/papers/r3_rahkonen.pdf there is
RJ> python code that might be useful and that can be used freely. That
RJ> script is doing basically the same thing, it takes ground control
RJ> points from external source and warps image automatically with gdal components."
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