[GRASS-dev] way to create PROJ_INFO and PROJ_UNITS
andrea.antonello at gmail.com
Wed Feb 27 07:23:02 EST 2008
> > But I do feel that it is important to have open formats, where open in
> > my opinion not only means that the specification is known and that
> > there is one unique software that can read the thing.
> Well, GRASS can import from and export to many different open formats...
> but I would not consider the native GRASS database a data transfer format
> in itself.
Alright, but since we started JGrass with the thought to extend GRASS
with our functionalities, we chose to base on the same format whenever
possible. I yet believe that has been and is a great choice we did.
> > If GRASS's
> > policy however is to have its own raster and vector formats and proj
> > format and let only GRASS itself and direct derivates have real fun on
> > them, then I will (have to) accept it, even if not agree.
> There isn't really any policy, but the I'm pretty sure compatiblity with
> other software that might want to access GRASS' internal files directly
> was not prominent in the minds of developers designing and extending
> GRASS' internal storage format. I don't think it's unreasonable to expect
> only GRASS to be able to reliably operate on its own internal formats? If
> we had to try and keep it consistent and unchanged so external software
> could always still read it it would be a huge amount of extra work as
> Glynn said.
> Regarding your proposal of adding another file to GRASS' internal
> co-ordinate system definition containing the co-ordinate system in WKT
> format, it can't be both ways - either it is considered part of the
> internal GRASS data format or it isn't. If it isn't, then GRASS will not
> use it for anything and there will be real way of testing whether it's
> correct and consistent or not. I.e., external software can't rely on it
> exactly representing the current co-ordinate system of the location. If it
> *is* considered part of the internal GRASS data format, then a lot of work
> will have to be put into keeping it in sync with PROJ_INFO/PROJ_UNITS - at
> present just modifying these files is enough to change the co-ordinate
> system of a GRASS location - that will no longer be possible. And how to
> handle co-ordinate systems that can only be specified in one format but
> not the other? I can see it just leading to a confusing mess.
I can see your points and respect the GRASS community decisions.
As such I promise I will never ask this one again (not sure I will be
able to :) ).
> If it would help though, I could properly document the PROJ_INFO /
> PROJ_UNITS format and how it differs from PROJ.4 format (note that
> GDAL/OGR includes lots of functionality for converting to and from PROJ.4
> format and it really isn't necessary to involve PROJ.4 itself at all,
> unless you want to use it for reprojection).
That would for sure be of great help to extend my knowledge in this issue.
Thanks for this discussion,
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