[OSRS-PROJ] WGS84 to RT90 problems..

Clifford J Mugnier cjmce at lsu.edu
Tue May 20 16:05:29 EDT 2003





Johan

Try reversing the sign of the rotation angles.  Your parameters may have
been computed with the left-handed European rotation convention.  (That's
one of the "inside" jokes in the international geodetic community, and the
responsible parties on the continent refuse to admit their error).

Cliff Mugnier
LOUISIANA STATE UNIVERSITY
--------------------------------
Hi everyone
Sorry to bother with a very newbie question (I assume)
I've seen people trying todo the same thing in the archives but I'm
still not able to get it right :c.

I'm trying to convert from WGS84 to RT90 2.5G W 0:-15

Feels like i've tried a zillion things but nothing gets me the correct
results.

I have a 7 param conversion params, Do I Need anything more?
I use :
"towgs84=-414.0978567149,-41.3381489658,-603.0627177516,-0.8550434314,2.1413465,-7.0227209516,1"
as I got from http://www.lm.se/geodesi/refsys/sweref-rt/sweref99-rt90.htm
sweref99 is ~same as WGS84.

Any example on how to convert coordinates using the 7param conversion
would be really nice

I'm using values fetched from my gps and transformed online to compare
the results :
http://www.lm.se/geodesi/program/gtransrv/gtransframe.htm

I'm using pj_transform with something like this (I've been changing this
back and forth so many times, it's probably all wrong now, hoping to get
a better example to work from)


TIA

PS: mails to list seems to work for me now, sry for all the extra posting


/Johan Björk


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