[GRASS-dev] backport r.proj -p, -g to 6.4.1svn?

Hamish hamish_b at yahoo.com
Wed Oct 13 03:33:36 EDT 2010


Moritz wrote:
> I would welcome this very much, but I would also like to
> ask : why not go one step further and add a flag which
> directly takes into account the extension and resolution of
> the original map to calculate a region for r.proj ?

Because it can+will do the wrong thing* and I think a human should
check over it, at minimum to pick a nice round resolution to use.
Versus doing the wrong thing, automatically.

[*] i.rectify tries to do this for you automatically, but it is
bad whenever there is convergence angle rotation between two
map projections (which is common; see 'g.region -n'). It is worst
for a square array when the angle is 45 deg, worst for a highly
rectangular array at 90deg rot. (see bug in old RC tracker)
Granted those extreme angles are more likely with i.rectify.


ie I think it is a task that requires careful consideration and
choices+compromises to be made.


Hamish



      


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