[Gvsig_english] gvSIG, reprojecting layers, strange behaviour and lack of understanding

[Wolfgang Qual]

Dear list,
I used the geoprocess "reproject" in order to change the projection of 
some layers from ETRS89 to Gauss-Krüger and observed some
strange things:
a) the size of the dbf-file of the shp was much bigger after the 
reprojection was done. I checked the field properties of both the source 
and target layer and
found that the field length was set to 18 for all columns, while the 
original columns had different field lengths (5 or 8)
b) there are several options for transformation within this geoprocess. 
I got the best result, when I chose "no transformation". However, the 
reprojected shapefile did not 100% fit
to the correct location in the target projection. There's a little shift 
of a few meters (x and y). Of course, it is possible to shift the whole 
layer a bit, but this is not a "clean" method. Shouldn't it fit with 
only reprojecting the layer?
c) Choosing the option "manual transformation", I have the possibility 
to set x- and y-translation, but the result was
not what I expected: specifiying 10 for x- and y-offset did not result 
in a equal shift of 10 meters in both directions. The distance in both 
directions was bigger!
c) when choosing EPSG transformation, several possibilities are listed, 
but the description was not clear to me. I just did not know which 
option to choose. Hopefully, the enclosed screenshot will explain better 
what I want to say here ;(
I searched for some information in the user manual of version 1.1.x, but 
the description there is not exhaustive. Some information on how to use 
this nice extension would be great.

Best,
Wolfgang




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