I just updated core.create_location.py and the location wizard in GRASS 7 to go along with Paul’s update to g.proj. Now the location wizard is creating correct locations for all available datums, when projections and datums are picked from a list.
So now the question is how to update GRASS 6.4.3 and 6.5
The location wizard can simply be updated or backported to work like it does in GRASS 7 now.
But core.create_location.py and g.proj will need to be updated first.
create_location just has to work with g.proj – though whatever happens, it will work a little differently than it did before with a risk of breaking any script that used it. I doubt there are many if any.
compatibility of the updated g.proj to the old g.proj is probably the main issue, however. Here are the choices
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Don’t updated anything because it may break someone’s script. Consequences: the location wizard will create problem locations if projections and datums are picked from a list
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Update g.proj by adding a new argument “datum”. Consequences: This will have no effect on any prior use of g.proj except for scripts that use “datum” as a shortcut to “datumtrans”. g.proj for GRASS 6 will be a little different from g.proj for GRASS 7 (argument “datumtrans” in GRASS 6.4.3+ becomes “datum_trans” in GRASS 7). Location wizard can be fixed.
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Update g.proj to have the same arguments as now in GRASS 7: change “datumtrans” to “datum_trans” and add new “datum” argument. Consequences: Because “datumtrans” is an acceptable abbreviation for “datum_trans”, this will not break scripts that use g.proj unless they use the “datum” shortcut for “datumtrans”. g.proj will have the same arguments in GRASS 6.4.3+ and GRASS 7. Location wizard can be fixed.
My vote is for #3. It fixes the datum and location problem, is consistent across GRASS 6.4.3-GRASS 7 and does not break previous use of g.proj any more than #2.
If all agree, then someone will need to backport Paul’s fixes to g.proj to GRASS 6.5 and 6.4.3.
Michael
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University
voice: 480-965-6262 (SHESC), 480-727-9746 (CSDC)
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www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu