[GRASS-dev] need update to core.create_location

[Michael Barton]

Thanks for the information Paul. This is a good tip to know for command-line typing. It is unfortunate, however, that this undocumented call was used in the Python scripting library. I agree with you that using "datum" for datums makes enormous sense. So hopefully we can get all straightened out.

I'll wait to do any committing until 1) you give me the goahead that you've fixed the issue in g.proj you mention and 2) I hear from Markus about updating create_location.

Thanks again for making such a fast fix for this.

Michael
______________________________
C. Michael Barton 
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University
Tempe, AZ  85287-2402
USA

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On Oct 2, 2012, at 1:40 AM, Paul Kelly <paul-grass at stjohnspoint.co.uk> wrote:

> Michael Barton wrote:
>> Arrgg.
>> 
>> Before Paul's update to g.proj today, it turns out that g.proj would
>> actually accept the argument "datum" as equivalent of the argument
>> "datatrans", even though this is not in the manual. I don't know if that
>> was intentional or an accident. So g.proj datumtrans=1 could also be
>> expressed as g.proj datum=1.
> 
> The g.proj option has always been called "datumtrans", but GRASS allows the user to shorten command-line options by dropping letters off the end, as long as they still unambiguously identify the option (and GRASS 7 extends this a bit further). So beforehand as there was no "datum" option, "datum" would have unambiguously identified "datumtrans". Now you need to type at least "datumt" in order to distinguish it from the new "datum" option.
> 
> I think as long as everywhere in GRASS 7 that might use the datumtrans= option is updated to use it correctly, there should be no problem. Of course we could also call the new option something other than "datum", but it seems like such a clear and obvious name that it seems to me a pity to have to change it!
> 
> One other thing - please don't backport for a few days; if I get time I want to try and make an improvement to the code so that the ellipsoid will always be changed if the datum is changed. As it is currently, it is theoretically possible to change the datum to one that is incompatible with the ellipsoid.
> 
> Paul