[Proj] WHAT WRONG WITH PROJECTION

[Roger Oberholtzer]

On Thu, 2011-02-24 at 13:16 -0500, Frank Warmerdam wrote:
> On 11-02-24 12:47 PM, Mustafa646 wrote:
> >
> > I have a shapefile with native projection "SWEREF99_TM" EPSG:2006 and i have
> > converted its projection to EPSG:4326 by ogr2ogr. The conversion was
> > successful, but when i compare the original shapefile with newly generated
> > file, there was a difference in width, the new file streatches in width.
> > Then i bublish this shapefile on Geoserver and tried to display it over
> > google map (by writing some code using Openlayers API). But the Layer could
> > not display. The important point to note is my code works with other files
> > published on Geoserver.
> >
> > I dont know where is exact problem, Can anybody help, where is problem ?
> 
> Mustafa,
> 
> EPSG:2006 is St. Lucia 1955 / British West Indies Grid.
> 
> +proj=tmerc +lat_0=0 +lon_0=-62 +k=0.9995000000000001 +x_0=400000
>      +y_0=0 +ellps=clrk80 +towgs84=-149,128,296,0,0,0,0 +units=m +no_defs
> 
> SWEREF99_TM appears to be EPSG:3006 which can translate effectively as
> UTM 33.
> 
>     +proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs

Personally, I use this for SWEREF99 TM:

"+proj=tmerc "                  // Projection
"+ellps=GRS80 "                 // Spheroid
"+k=0.9996 "                    // Scale factor at central meridian
"+x_0=500000 "                  // False easting
"+y_0=0 "                       // False northing
"+lon_0=15.0 "                  // Longitude of central meridian
"+lat_0=0.0 "                   // Latitude of origin
"+towgs84=0,0,0,0,0,0,0 "       // Datum
"+no_defs"

This results in near perfect matches with the reference data published
by the Swedish Survey Authority. See
http://www.lantmateriet.se/upload/filer/kartor/geodesi_gps_och_detaljmatning/Referenssystem/kontrollpunkter_sweref99tm.pdf

See http://www.lantmateriet.se/templates/LMV_Page.aspx?id=4219 for a
general description - sorry it is in Swedish, I thought there was an
English version before but do not see it now.


Yours sincerely,

Roger Oberholtzer

OPQ Systems / Ramböll RST

Office: Int +46 10-615 60 20
Mobile: Int +46 70-815 1696
roger.oberholtzer at ramboll.se
________________________________________

Ramböll Sverige AB
Krukmakargatan 21
P.O. Box 17009
SE-104 62 Stockholm, Sweden
www.rambollrst.se