User:Kagee/Converting NGO WGS84
NGO Akse III
echo 'east-scaled north-scaled' | LC_ALL=C cs2cs +proj=tmerc +lat_0=58 +lon_0=10.722917 +k=1 +x_0=0 +y_0=0 +a=6377492.018 +b=6356173.508712696 +units=m +towgs84=278.3,93,474.5,7.889,0.05,-6.61,6.21 +no_defs +to +proj=latlong +datum=WGS84 -f '%.13f'
Tests from aafjord-1630vbas.sos
id : type .. coord order east north height east-scaled north-scaled east north (as staded by kart.statkart.no when converting from "NGO1948 Gauss-K. Akse 3" to "EU89-Geografisk" east north (from cs2cs (-f '%.13f')) east north (result from line above, rounded manually at 6. and 7. decimal)
.PUNKT 26: Ferjekai ..NØH 67346310 -3333560 260 ...KP 1 -33335.60 673463.10 10.0351573957103 64.0432636388396 10.0351563744381 64.0432636022641 10.035156 64.0432636
.PUNKT 33: Kommunedele ..NØH 66807090 306990 26560 ...KP 1 3069.90 668070.90 10.7802329241666 63.9965043442247 10.7802319011236 63.9965043149692 10.780232 63.9965043
.PUNKT 1938: Vegbom ..NØH 66398470 -2393030 2400 ...KP 1 -23930.30 663984.70 10.2291617894231 63.9590230458252 10.2291607711611 63.9590230118958 10.229161 63.9590230
Other stuff
hildenae@toolmaster:~$ proj -le | grep bessel bessel a=6377397.155 rf=299.1528128 Bessel 1841
The ellipsoid used in NGO1948 is a modified Bessel ellipsoide. [1] It's paramters are:
- a = 6 377 492.0176
- b = 6 356 173.5083
- f = 0.0033427731816
- 1/f = 299.15281285
cs2cs +proj=latlong +datum=WGS84
+to +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0
+x_0=0.0 +y_0=0 +k=1.0 +units=m +no_defs
Attempt one
Assuming tmerc : Transverse Mercator equals Gauss-Krüger (Transversal Mercator) as stated in [1].
cs2cs +proj=tmerc +a=6377492.0176 +b=6356173.5083 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +no_de +to +proj=latlong +datum=WGS84
NGO-3
proj +proj=tmerc +lat_0=58 +lon_0=10.722917 +k=1.000000 +x_0=0 +y_0=0 +a=6377492.0176 +b=6356173.5083 +towgs84=278.3,93,474.5,7.889,0.05,-6.61,6.21 +pm=oslo +units=m +no_defs no_defs
Ved bruk av NGO-Norsk aksesystem an- gis nord-koordinat i meter nord for 58° nord. Øst-koordinat angis i meter fra berøringsme- ridianen. Det betyr at posisjoner på vestsi- den av en berøringsmeridian får negative øst-koordinater. Koordinatene i NGO-Norsk aksesystem er ikke påført noen fast måle- stokkskorreksjon. Skaleringsfaktoren er med andre ord 1.0.
Berøringsmeridianen for NGO-3 er 10° 43’ 22.5” øst/ 10.722917 / 10 43.375
[2]
If you look in the PROJ4 documentation, and look for a file for either ESRI or EPSG, and search for Oslo, you get some references that look familiar:
- NGO 1948 (Oslo)
+proj=longlat +a=6377492.018 +b=6356173.508712696 +towgs84=278.3,93,474.5,7.889,0.05,-6.61,6.21 +pm=oslo +no_defs no_defs
for the longlat,
- NGO 1948 (Oslo) / NGO zone I
+proj=tmerc +lat_0=58 +lon_0=6.056250000000003 +k=1.000000 +x_0=0 +y_0=0 +a=6377492.018 +b=6356173.508712696 +towgs84=278.3,93,474.5,7.889,0.05,-6.61,6.21 +pm=oslo +units=m +no_defs no_defs
and so on for the other zones. I don't know if this is precise enough, though.
Roger
Almost works, what is wrong
echo '-8438.20 681046.80' | cs2cs +proj=tmerc +lat_0=0 +lon_0=10.722917 +k=1.000000 +x_0=0 +y_0=-6430707.919 +a=6377492.0176 +b=6356173.5083 +towgs84=278.3,93,474.5,7.889,0.05,-6.61,6.21 +pm=oslo +units=m +no_defs -f '%.8f' echo '-8438.20 681046.80' | cs2cs +proj=tmerc +lat_0=0 +lon_0=10.722917 +k=1.000000 +x_0=0 +y_0=-6430707.919 +a=6377492.0176 +b=6356173.5083 +proj=latlong +datum=WGS84 +no_defs -f '%.8f'
gives
- 10.54975342 64.11244149
statkart gives
- 10.54433467 64.11280671
this is a offset of approx 5.55 km and 444 meters [4]
Sources
- [1] http://www.skogoglandskap.no/filearchive/ngo_gps.pdf
- [2] http://osgeo-org.1803224.n2.nabble.com/GRASSLIST-323-GRASS-and-the-Norwegian-coordinate-systems-NGO48-tp1853978p1853981.html
- [3] http://trac.osgeo.org/proj/wiki/GenParms
- [4] http://en.wikipedia.org/wiki/Decimal_degrees
- [5] http://www.epsg-registry.org/