[GRASS5] Problem converting NAD27 to NAD83.

Hello, I am having problems with v.proj (and r.proj) when projecting vectors from a NAD27 database to NAD83 use GRASS 6.0

This is the output from the v.proj command:

Input Projection Parameters: +proj=utm +zone=10 +a=6378206.4 +rf=294.9786982 +no_defs +nadgrids=ntv1_can.dat
Input Unit Factor: 1

Output Projection Parameters: +proj=utm +zone=10 +a=6378137 +rf=298.257222101 +no_defs +towgs84=0.000,0.000,0.000
Output Unit Factor: 1
WARNING: The vector 'lines' already exists and will be
          overwritten.

Creating vector file...
pj_transform() failed
cause: failed to load NAD27-83 correction file
Error in pj_do_transform

This is my PROJ_INFO file:

name: UTM
datum: nad83
dx: 0.000000
dy: 0.000000
dz: 0.000000
proj: utm
ellps: grs80
a: 6378137.0000000000
es: 0.0066943800
f: 298.2572221010
zone: 10

This is my DEFAULT_WIND file:
proj: 1
zone: 10
north: 6665000
south: 5300000
east: 696621
west: 332705
cols: 72783
rows: 273000
e-w resol: 5.00001374
n-s resol: 5

Any suggestions?
--
Craig Funk
funkmeister -at- lynxseismicdata -dot- com

Hello Craig

On Thu, 7 Apr 2005, Craig Funk wrote:

Hello, I am having problems with v.proj (and r.proj) when projecting vectors from a NAD27 database to NAD83 use GRASS 6.0

This is the output from the v.proj command:

Input Projection Parameters: +proj=utm +zone=10 +a=6378206.4 +rf=294.9786982 +no_defs +nadgrids=ntv1_can.dat
Input Unit Factor: 1

Output Projection Parameters: +proj=utm +zone=10 +a=6378137 +rf=298.257222101 +no_defs +towgs84=0.000,0.000,0.000
Output Unit Factor: 1
WARNING: The vector 'lines' already exists and will be
        overwritten.

Creating vector file...
pj_transform() failed
cause: failed to load NAD27-83 correction file
Error in pj_do_transform

The most common cause for that error is that the points you are trying to re-project fall outside the area covered by the datum shift grid file (ntv1_can.dat). Are you sure it is the correct file for your area (Canada).

If you are having trouble with the grid shift files you could try doing a less precise datum transformation using a 3 or 7-parameter transformation. Re-run g.setproj in the NAD27 location to set up your datum parameters.

Paul

This is my PROJ_INFO file:

name: UTM
datum: nad83
dx: 0.000000
dy: 0.000000
dz: 0.000000
proj: utm
ellps: grs80
a: 6378137.0000000000
es: 0.0066943800
f: 298.2572221010
zone: 10

This is my DEFAULT_WIND file:
proj: 1
zone: 10
north: 6665000
south: 5300000
east: 696621
west: 332705
cols: 72783
rows: 273000
e-w resol: 5.00001374
n-s resol: 5

Any suggestions?
--
Craig Funk
funkmeister -at- lynxseismicdata -dot- com

_______________________________________________
grass5 mailing list
grass5@grass.itc.it
http://grass.itc.it/mailman/listinfo/grass5

The most common cause for that error is that the points you are trying to re-project fall outside the area covered by the datum shift grid file (ntv1_can.dat). Are you sure it is the correct file for your area (Canada).

If you are having trouble with the grid shift files you could try doing a less precise datum transformation using a 3 or 7-parameter transformation. Re-run g.setproj in the NAD27 location to set up your datum parameters.

Paul

Thanks Paul,

It ends up that the ntv1_can.dat file did not appear to be installed properly. Where should the file live? I placed it in etc/nad directory of the GRASS installation and then the r.proj and v.proj commands worked fine.

I built my GRASS install from source on a Mac G5. Is this maybe a problem with the makefiles?

Craig

On Thu, 2005-04-07 at 12:40 -0600, Craig Funk wrote:

>
> The most common cause for that error is that the points you are trying
> to re-project fall outside the area covered by the datum shift grid
> file (ntv1_can.dat). Are you sure it is the correct file for your area
> (Canada).
>
> If you are having trouble with the grid shift files you could try
> doing a less precise datum transformation using a 3 or 7-parameter
> transformation. Re-run g.setproj in the NAD27 location to set up your
> datum parameters.
>
> Paul
>
>
Thanks Paul,

It ends up that the ntv1_can.dat file did not appear to be installed
properly. Where should the file live? I placed it in etc/nad directory
of the GRASS installation and then the r.proj and v.proj commands
worked fine.

I built my GRASS install from source on a Mac G5. Is this maybe a
problem with the makefiles?

Did you build GDAL with --with-static-proj4? This option is not
compatible with GRASS.

--
Brad Douglas <rez@touchofmadness.com>

On 7-Apr-05, at 2:30 PM, Brad Douglas wrote:

Did you build GDAL with --with-static-proj4? This option is not
compatible with GRASS.

No, it is not compiled with that option.

Craig

Craig Funk wrote:

It ends up that the ntv1_can.dat file did not appear to be installed
properly. Where should the file live? I placed it in etc/nad directory
of the GRASS installation and then the r.proj and v.proj commands
worked fine.

I built my GRASS install from source on a Mac G5. Is this maybe a
problem with the makefiles?

That file should be installed into etc/nad by lib/proj/Makefile. Check
the output from "make -C lib/proj" in case there is an error which
prevents it from being installed.

--
Glynn Clements <glynn@gclements.plus.com>