[GRASSLIST:2207] Re: Norwegian users?

[Andreas Lange]

Hi Morten,

no, i am not from norway. 
But if your data from GPS and maps and imported into grass do not fit it
may be from that grass currently does no map datum transformation. The
values for datum, dx, dy, dz are currently for reference and upward
compatibiliy only. That may give you errors in the range of some meters
up to 100s of meters, depending on projection, ellipsoid etc.

Anyone volunteering in helping me with integrating the new proj library
and map datum support in GRASS?

cu,

Andreas

Morten Sickel wrote:
> 
> Are there any other Norwegian grass users around? I have seen a couple on the
> mailing lists, but I am a bit curious to see if there are any others.
> 
> Has anybody else tried to use files in NGO-projection? I have tried to
> integrate some files in that projection with data originally aquired as
> lat/lon from a GPS, but the datasets doesn't fit too well.
> 
> Also, If there are any users in the Oslo / Akershus / Østfold area, I might
> have a few hours of job for you.
> 
> (In case anybody else gets curious, NGO projection is defined as follows:
> GRASS:~ > cat /home/grassdata/NGO/PERMANENT/PROJ_INFO
> name: Transverse Mercator
> datum: NGO48
> dx: 319.080000
> dy: 37.810000
> dz: 463.570000
> proj: tmerc
> ellps: NGO48
> a: 6377492.0175999999
> es: 0.0066743723
> f: 299.1528083933
> lat_0: 58.0000000000
> lon_0: 8.3895833333
> k_0: 1.0000000000
> x_0: 0.0000000000
> 
> Other lon_0 values might be used in other parts of Norway)
> 
> --
> Morten Sickel
> GIS Consultant
> Drøbak, Norway

-- 
Andreas Lange, 65187 Wiesbaden, Germany, Tel. +49 611 807850
Andreas.Lange at Rhein-Main.de - A.C.Lange at GMX.net