[postgis-users] NAD conversion problem

[Richard Greenwood]

On Tue, Dec 16, 2008 at 9:57 PM, Richard Greenwood
<richard.greenwood at gmail.com> wrote:
> On Mon, Dec 8, 2008 at 6:08 PM, Dylan Beaudette <debeaudette at ucdavis.edu> wrote:
>>> Richard Greenwood wrote:
>>> 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
>
> On my Ubuntu 8.04 with a binary proj installed from the Ubuntu repository I get:
> echo '-121.000000 37.000000' | cs2cs  +proj=latlong +datum=NAD27 \
> +to +proj=latlong +datum=NAD83
> 121dW   37dN 0.000   # obviously no datum transform
>
> So I fetched the proj source and proj-datumgrid-1.4.zip and did
> ./configure make make install. But still no datum transform from my
> new copy of proj. So I did:
>
> $ nad2bin <src/proj-4.6.1/nad/proj-datumgrid-1.4/conus.lla conus
>
> and copied it to  /usr/share/proj/ and finally I get the expected results:
>
> $ echo '-121.000000 37.000000' | cs2cs  +proj=latlong +datum=NAD27 +to
> +proj=latlong +datum=NAD83
> 121d0'3.704"W   36d59'59.804"N 0.000
>
> The only copy of conus that $ locate found on my system prior to my
> making it with nad2bin was in /usr/lib/grass/etc/nad/  Probably doing
> $ export PROJ_LIB=/usr/lib/grass/etc/nad/ would have saved me making
> conus.

Following up on this with a little morning clarity...  If you un-zip
the *.lla fiiles in proj-datumgrid-1.4.zip into the
proj/nad directory before you build, then configure, make, install
does convert them to binary and copy them to the share/proj directory.

However, I am troubled that the Ubuntu proj distribution does not seem
to include the grid ship files.

-- 
Richard Greenwood
richard.greenwood at gmail.com
www.greenwoodmap.com