Hi,
Sorry everybody, grass6.0 failed because I made a mistake for the .gsb file, I
copy the file again, It work now.
Thanks,
Feng
---------- Forwarded Message ----------
Subject: [GRASSLIST:7969] Fwd: Re: Fwd: Re: nad27/nad83 datum conversion for
canada using Ntv2
Date: Thursday 18 August 2005 11:14
From: Feng Tan <feng@lynxseismicdata.com>
To: GRASSLIST@baylor.edu
Hi,
Regarding the ntv2.gsb for canada in grass6.0
After I put NTV2_0.GSB file in the $GISBASE/etc/nad , I went to $GISBASE/etc
edited datumtransform.table and replaced ntv1_can.dat with NTV2_0.GSB, I
start a new nad27 location by chosing NTV2_0.GSB, then in my nad83 location I
use v.proj command to do the nad27/nad83 conversion, it also failed:
it says:
pj_tranform() failed
cause: failed to load NAD27-83 correction file
Error in pj_do_transform
Please help!!!
Feng
---------- Forwarded Message ----------
Subject: [GRASSLIST:7962] Re: Fwd: Re: nad27/nad83 datum conversion for
canada using Ntv2
Date: Wednesday 17 August 2005 15:54
From: Feng Tan <feng@lynxseismicdata.com>
To: Paul Kelly <paul-grass@stjohnspoint.co.uk>
Cc: GRASSLIST@baylor.edu
Hi, Paul,
Thank you very much for the answer. I went to $GISBASE/etc edited
datumtransform.table and replaced ntv1_can.dat with NTV2_0.GSB, I start a new
location by chosing NTV2_0.GSB, but cs2cs failed. I did following
IN_PROJ="+proj=utm +zone=10 +a=6378206.4 +rf=294.9786982 +no_defs
+nadgrids="$GISBASE/etc/nad/NTV2_0.GSB""
OUT_PROJ="+proj=utm +zone=10 +a=6378137 +rf=298.257222101 +no_defs
+towgs84=0.000,0.000,0.000"
echo "889298.45 8682992.65" |cs2cs -f %.7f $IN_PROJ +to $OUT_PROJ
* * 0.0000000
what is wrong???
Thanks,
Feng
On Wednesday 17 August 2005 14:22, you wrote:
On Wed, 17 Aug 2005, Feng Tan wrote:
> I just did some testing about nad27/nad83 datum conversion for a point in
> Alberta, Canada using GRASS6.0 comparing with ESRI ARCGIS9.1, following
> is the result, it has about +-100m difference with or without NTV2_0.GSB.
> I wish GRASS can implement newer version of Canadian National
> Transformation NTV2_0.GSB nad27/nad83 datum shift grid file soon, so we
> can use GRASS more confidently.GRASS (and PROJ.4) *can* use NTv2 GSB (binary) files and has been able to
since the datum shifting support was added in 5.3. I'm not sure what
your problem is here. What are you trying to change?
Put the gsb file in the $GISBASE/etc/nad directory and edit the PROJ_INFO
file for your NAD27 location to point to the new file.Paul
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