[GRASS-dev] v.info: projection info wrong

Markus Metz markus.metz.giswork at googlemail.com
Wed Jan 25 03:12:55 EST 2012

On Wed, Jan 25, 2012 at 2:46 AM, Martin Landa <landa.martin at gmail.com> wrote:
> Hi,
> 2012/1/25 Hamish <hamish_b at yahoo.com>:
>> Map_info->proj likely needs some work to finish taking advantage of it in
>> the libs & modules, if this "assert" failsafe is to be used with vector
>> maps. (for my 2c I think it is worth the trouble to keep going with that;
>> I don't think a .prj file with v.pack is enough to catch all cases, or
>> robust enough. the mis-copy could just as well be a manual filesystem copy
>> as a v.pack transportation)
> I would tend to agree. Proj info should be saved in head file
> similarly to rasters (cellhd). As I noted earlier Vect_open_*() should
> check if proj info in the head file differs from location settings and
> at least to print some warning about this mismatch.
It would not require a lot of modifications. First of all, projection
info would need to be written to the head file. Even though projection
info is stored in struct Map_info, it is neither read from nor written
to the header. That would cause a warning when opening a GRASS7 vector
with GRASS 6, but that's not tragic.

AFAICT it was never actually implemented, even if there is history and
background about its purpose.

Markus M

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