[Qgis-user] How to downscale shapefile data

[Andre Joost]

Dear Francesco,

please use a meaningful topic so that others can search for it.

Am 06.07.2015 um 10:50 schrieb 
francesco.maicu at ve.ismar.cnr.it:
> Dear all,
> I have a shape file tha for a certain reason has wrong coordinates.
> The areal geometry data originally come from a dgn file with EPSG3004
> coordinates, but now as I edited and exported from Geomedia, they have been
> multiplied for a factor 100, ie the exported shape has coordiantes 100times
> greater than real ones.
> How can I go back (re-translate) to EPSG3004 coordinates?
> I saved a custom CRS ading to EPSG3004 string,the keyword +to_meter=0.01 ,
> but it doesn't work.

EPSG:3004 is defined as:

+proj=tmerc +lat_0=0 +lon_0=15 +k=0.9996 +x_0=2520000 +y_0=0 +ellps=intl 
+towgs84=-104.1,-49.1,-9.9,0.971,-2.917,0.714,-11.68 +units=m +no_defs

If you want to change the units, you have to replace the +units=m part 
with +to_meter=0.01:

cs2cs +proj=tmerc +lat_0=0 +lon_0=15 +k=0.9996 +x_0=2520000 +y_0=0 
+ellps=intl +towgs84=-104.1,-49.1,-9.9,0.971,-2.917,0.714,-11.68 
+to_meter=0.01 +no_defs +to +init=epsg:3004 <in.csv >out.txt

in.csv:
250000000 450000000

out.txt:
2500000.00	4500000.00 0.00

HTH,
André Joost