[Qgis-user] Re: How can we change x, y spatial reference system units to lat,long format in qgis?

[Zoltan]

Ah I see, sorry for not fully understanding your problem :)

The Autocad vector file will be georeferenced the origin will be 0,0 which
is a point in the Atlantic Ocean in WGS84

The cad files will have their XY points lines etc in meters relative to that
origin.
So when you export to shape files the shape files too will have their XY
points lines etc in meters relative to that origin,

 Just telling QGis that you want to use WGS84 to project those lines points
etc isn't enough you need shape or cad files that store distances in radians
not meters to be able to get QGis to put the points where you want them and
have their 'true' lat long displayed.

I think GRASS or gdal can actually do this for you, but you need to
understand proj4 formats, 

http://proj.maptools.org/gen_parms.html 

Or do what I did which was to use a script -a quick and dirty hack - to
calculate lat long from the spatial index and store them back in a
Spatialite database in a table with another spatial reference column for lat
long points lines etc

i.e. as your original cad files have distances in meters and origin at 0,0
(probably)so will the exported shapefile.  So when you import the shapefile
QGis just sees meters not radians and plots the points accordingly.

I hope that helps






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