[Gvsig_english] raster georeferencing in gvSIG 1.9

ernesto sferlazza e.sferlazza at gmail.com
Sat Sep 19 22:39:21 CEST 2009


Hello list and developers
I have some questions, wishes and remarks on the issue:
1) the 1st polynomial algorithm works fine with a 8 bit raster, but if
the raster to be georeferenced is 1 bit (b/w), the values of the
resampled output raster are stretched to a 8 bit scale (256 values).
The problem is that the original values (0 and 1) does not correspond
to the extremes of the new range of  values (0 and 255), so that is
very difficult to find a suitable palette for a correct visualization.
2) it should be useful allow user to choose the output value of
"nodata" cells in the output resampled raster;
3) options -> georeferencing algorithm : what is intended for "afine"
transformation? . I know that affine transformation is a 1st order
polynomial (minimum 3 points, errors and rms are calculated with more
than three points, while in the GCP panel errors and rms values
greater than zero appears with more than 1 point). Anihow, when I
click "test georeferencing" (I think it would be better "apply" or
"perform" georeferencing) nothing happens.
4) options -> georeferencing algorithm: in the list of polynomial
transformation the term "degree" (of polynomial) is indicated as
"sexagesimal degree" (maybe a translation mistake).
5) a wish for next versions: fractional polynomial rectification tranform

Best regards
-- 
ing. Ernesto Sferlazza
responsabile nodo provinciale di Agrigento del SITR Sicilia
resp. gruppo Sistema Informativo Territoriale
Provincia regionale di Agrigento
sede istituzionale: piazza Aldo Moro, 1 - 92100 AGRIGENTO
sede operativa: via Acrone, 27 - 92100 AGRIGENTO
cell. 3392718463 (personale)
       3316874296 (aziendale)
tel. uff 0922593752


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