[postgis-users] NAD conversion problem

[Dylan Beaudette]

On Monday 08 December 2008, Richard Greenwood wrote:
> On Mon, Dec 8, 2008 at 12:19 PM, Peter N. Schweitzer
>
> <pschweitzer at usgs.gov> wrote:
> > Richard Greenwood wrote:
> >> On Thu, Dec 4, 2008 at 1:19 PM, Peter N. Schweitzer
> >>
> >> <pschweitzer at usgs.gov> wrote:
> >>> Hello,
> >>>
> >>> I have two PostgreSQL installations.  One uses 8.3.3 with PostGIS
> >>> 1.3.3, GEOS 3.0.1, and PROJ 4.6.1 (with proj-datumgrid-1.4).  With it I
> >>> am able to
> >>> run a command like
> >>>
> >>> update county set nad27_geom=ST_Transform(the_geom,4267);
> >>>
> >>> My newer installation uses 8.3.5 with PostGIS 1.3.4, GEOS 3.0.3, and
> >>> PROJ 4.6.1.  With this system I get the error message
> >>>
> >>> WARNING:  transform: -38 (failed to load NAD27-83 correction file)
> >>> ERROR:  transform: couldn't project point: -38 (failed to load NAD27-83
> >>> correction file)
> >>>
> >>> I know that proj-datumgrid-1.4.zip must be unzipped in the nad/
> >>> directory of proj-4.6.1 PRIOR to running configure.  I have done this.
> >>> I have also recompiled and reinstalled proj, GEOS, and PostGIS in that
> >>> order, running ldconfig at the end of each step.  The directory
> >>> /usr/local/share/proj on each of these systems is identical.
> >>>
> >>> I've tried recreating the database cluster, starting and stopping
> >>> the database instance, rebooting the machine, dropping and rebuilding
> >>> the spatial database, all to no avail.
> >>>
> >>> So I'm looking for some setting that I may have missed, some
> >>> environment variable, or some trick to tell libproj.so.0.5.5 where its
> >>> transform files should go.
> >>>
> >>> Both systems run Slackware 12.1.
> >>>
> >>> I'm at wit's end.  Any clues?
> >>>
> >>> Pete
> >>
> >> PROJ_LIB is an environment variable that points to the directory
> >> containing grid shift files and EPSG parameter files.
> >>
> >> The grid shift files are binary and platform specific. Is it possible
> >> that you are using Windows grid shift files on a Linux system?
> >>
> >> You could also rule out issues related to the different versions of
> >> Postgres and PostGIS on you two systems by testing at the command line
> >> with the cs2cs utility which is a part of Proj.
> >
> > Rich,
> >
> > Thanks for your counsel.  The example using cs2cs from its documentation
> > worked the same on both systems, executed from the command line.
> >
> > I believe the grid shift files are slightly different, even though I
> > thought I had installed the same versions.  As a test, I copied the
> > /usr/local/share/proj directory from the older system (the one that
> > does the datum shift without complaint) to the newer one, and the
> > ST_Transform completes without error.  So I believe that is the source
> > of the problem.
> >
> > But there is only one link on http://trac.osgeo.org/proj/ for the datum
> > shift file package.  If the package is OS-specific I would
> > expect to see more than one.  So I am puzzled and worried that next
> > time I may face the same problem again.
> >
> > Peter
>
> The files in http://svn.osgeo.org/metacrs/proj/trunk/proj/nad/ are
> ASCII. In the nad directory, you need to do:
>   ./configure
>   make
>   install
> to create the binary grid shift files that proj actually uses. (Proj
> doesn't read the ASCII files). And I'm not sure that the
> config-make-install of the proj program does the nad directory.
>
> Rich

REALLY?

I have never heard that the config-make-make install steps would not process 
the NAD grid files... Can someone verify this?

Cheers,

Dylan

-- 
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341