gdal_translate deprecate '-a_srs' for '-prj' or '-projdef'

[matt.wilkie@…]

For gdal_translate the "-a_srs" command line option for overriding the output
projection definition is hard to remember as it is non-sensical outside a small
group of experts. It would be better to use "prj" or "proj" as projection is a
term in much wider use, more people know it.

gdal_warp uses -t_srs and -s_srs for target and source projection definitions
respectively.  Even if the request to use prj instead of srs is rejected, at
least harmonize the options between the utilities; change -a_srs to -t_srs for
gdal_translate.

[warmerdam]

Matt, 

I wouldn't want to change -a_srs to -t_srs because -a_srs means "assign SRS"
while -t_srs means "target SRS" which in my mind implies the target of a 
reprojection. 

SRS is actually more correct than proj since SRS includes projections and
non-projected coordinate systems like geographic coordinates. 

In short, while I appreciate the feedback I am not going to act on either 
suggestion. 

[matt.wilkie@…]

ahhh, assign, source and target, that makes sense. Maybe it would help if that
was spelled out in the docs, something like this:

* a_srs srs_def: Assign the Spatial Reference Set (projection) for the output
file. The srs_def may be any of the usual GDAL/OGR forms, complete WKT, PROJ.4,
EPSG:n or a file containing the wkt.
[in http://www.remotesensing.org/gdal/gdal_utilities.html]

I still think using prj instead of srs is a good idea. Even you are using the
term "projection" instead of "spatial reference set" on that page. :)