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Help to know Swedish projection (proj4string(myfile) <- CRS(""))

3 messages · gianni lavaredo, Kranstauber, Bart, Roger Bivand

Original
Kranstauber, Bart
# 
Seems there are rather a lot of varieties on these systems

http://spatialreference.org/ref/?search=RT90

If you find the right one there click on the proj4 there is the right 
string if i'm not mistaken
http://spatialreference.org/ref/epsg/3022/proj4/

maybe the epsg code it self can be used as well if i read the CRS help
On 08/26/2010 02:29 PM, gianni lavaredo wrote:
Roger Bivand
#
On Thu, 26 Aug 2010, gianni lavaredo wrote:

            

      
      
      
    

        
Google "RT 90 system and SWEREF 99 (TM)" gives you:

http://www.lantmateriet.se/upload/filer/kartor/geodesi_gps_och_detaljmatning/Referenssystem/Oversikt_eng.pdf

See also:

http://spatialreference.org/ref/epsg/3006/

and search output for RT90 and SWEREF99. Grids & Datums (August 2004):

http://www.asprs.org/resources/GRIDS/

for suggestions for a +towgs84= parameter set to do datum transformation.

Almost always http://spatialreference.org and Grids & Datums (if available 
for the country of interest) yield useful results.

Roger

PS. It is always useful to verify the correctness of CRS definitions by 
transforming to geographical coordinates in WGS84 datum and overlaying a 
display on a known map, shuch as Google Earth.