[Gvsig_english] measuring (scaling) of distances e.g.

[Francisco José Peñarrubia]

Hi Klaus.

It seems you are using projected coordinates vs unprojected coordinates. 
gvSIG doesn't reproject images (vectorial data yes).
Your options:
a) You can choose in gvSIG EPSG:4326 (your image is in WGS84) and 
digitalize again.
b) You can use gdaltools to reproject your image to projected 
coordinates in order to convert it to EPSG:32737 and digitalize again.
c) (I guess you don't want to digitalize again.... ;-) ).
     - Open a new view with EPSG:4326
     - Add your image if you want.
     - Add your shape file. Make sure when you add the shape file, you 
are telling gvSIG that your shp file has coordinates in EPSG:4326. You 
can measure and your distances should be ok (gvSIG will reproject form 
degrees to meters).
     - Last. I prefer this:
          -Reproject your vector data to EPSG:32737. (Open a new view 
with EPSG:32737, add your shape file (be careful, tell gvSIG this shp 
file is in EPSG:4326). gvSIG will ask you if you want to reproject. Say 
yes and save with a different name.
         - Reproject your image to EPSG:32737. You can use gdal-tools.


More information about EPSG transformations (and I guess data you may use):
http://luparumeru.blogspot.com/

Hope it helps.

Fran.

PS: About unintuitive method to move points, I agree. We may change it, 
because this method was choosed along time ago. Is the same method that 
uses Autocad r12 to move points. That's the reason to do it like this, 
the idea was to ease the digitalization to designers coming from 
AutoCAD. Of course, it will be a good idea to develop (I think there are 
some plugins that already did) a new easy tool.



El 16/12/2010 6:21, Klaus Schaefer escribió:
> Hi Fran,
>
> thanks for helping! I'm using the EPSG:32737 projection and this is what my
> satellite picture's properties say:
>
> Information des Datensatzes
> Datei: 
> D:\100 Satellite Pictures\SAME_CONV.TIF
> Größe: 
> 827 MB (867.068.623 bytes)
> Breite x Höhe: 
> 27979.0 X 10329.0
> Format: 
> TIF
> wird georeferenziert: 
> ja
> Anzahl der Bänder: 
> 3
> Datentyp: 
> Byte
>
> Geografische Koordinaten
> oben links: 
> 37.679387634131885, -4.04751041305502
> Unten rechts: 
> 37.80532044122358, -4.094418817818234
> oben rechts: 
> 37.80539297284078, -4.0477077042434
> unten links: 
> 37.679315102514686, -4.0942215266298545
> Pixel Größe X: 
> 4.503568344433034E-6
> Pixel Größe Y: 
> -4.522326805579799E-6
> Rotation X: 
> -7.022133526567165E-9
> Rotation Y: 
> -7.051402422522061E-9
>
> Quelle
> Band 1: 
> Type=Byte, ColorInterp=Red
> Band 2: 
> Type=Byte, ColorInterp=Green
> Band 3: 
> Type=Byte, ColorInterp=Blue
>
> Projektion
>    GEOGCS["WGS 84",     DATUM["WGS_1984",       SPHEROID["WGS
> 84",6378137,298.2572235630016,         AUTHORITY["EPSG","7030"]],
>        AUTHORITY["EPSG","6326"]],     PRIMEM["Greenwich",0],
>      UNIT["degree",0.0174532925199433],     AUTHORITY["EPSG","4326"]],
>
> Metadaten
> AREA_OR_POINT: 
> Area
> TIFFTAG_XRESOLUTION: 
> 1
> TIFFTAG_YRESOLUTION: 
> 1
> TIFFTAG_RESOLUTIONUNIT: 
> 2 (pixels/inch)
>
>
>
> I've also attached the gvSIG logfiles. Thanks for looking into this!
>
> Best regards
> Klaus
>
> http://osgeo-org.1803224.n2.nabble.com/file/n5840924/gvSIG.log gvSIG.log

-- 
Fran Peñarrubia
Scolab
www.scolab.es

Asociación gvSIG
www.gvsig.com