[Proj] truble to translate coordinates from WGS84 to EPSG:31287
Markus Hetzmannseder
hetzi at algebra.uni-linz.ac.at
Thu Oct 28 03:11:58 EST 2010
Hallo,
i have trubles to translate WGS84 coordinates to EPSG:31287. This is
needed at the Openstreetmap Projekt for the correct projection of OSM-data
to the austrian geoimage.at WMS-service. For the OSM-editor JOSM there is
a plugin epsg31287, that should do the job and in its calculations it is
based on proj. That plugin is based an proj is working, its not working
really correct. It is producing a shift of about 30 metre and that shift
is only local, in other regions of austria the shift has a different
length and different direction.
For debugging that shift i started to use proj directly, and it is
producing the same shift in its calculations like the JOSM-plugin.
The correct proj arguments for EPSG31287 should be:
+proj=lcc +lat_1=49 +lat_2=46 +lat_0=47.5 +lon_0=13.33333333333333
+x_0=400000 +y_0=400000 +ellps=bessel
+towgs84=577.326,90.129,463.919,5.137,1.474,5.297,2.4232
+units=m +no_defs
For my reference i use the coordinate translation service of geoland.at
(http://www.geoland.at/geolandcoord/eingabe.aspx)
The results are for some example points:
WGS84 proj-EPSG31287 geoland.at-EPSG31287
14.2833092 48.3098392 470439.28 490437.40 470507.17 490503.03
16.371345 48.211996 625637.33 483542.58 625724.57 483601.75
9.747076 47.503042 130035.17 406569.01 130056.24 406637.26
The geoland.at projection is, as far i know, the real projection the
WMS-service (http://wms.geoimage.at) is using.
Any hints where the difference could be come from?
thx a lot
Markus Hetzmannseder
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