[GRASS-dev] g.region print flags combination

[Martin Landa]

Hi all,

I would like to summarize all complication with the new behaviour of
g.region. I would like also to ask you some question, to fix and close
this issue finally;-)

1) The -g flag can be used in combination with all print flags, e.g.

g.region -cg

I think it is without problem. There was idea to add a new flag for
shell script style. I hope it is possible to use the -g flag for this
work as well.

2) It is possible to mix print flags, e.g.

g.region -pc

or for parsable output

g.region -pcg

There should not be any problem.

3) The -p flag was changed.

projection: 99 (Krovak)
zone: 0
datum: towgs84=570.8,85.7,462.8,4.998,1.587,5.261,3.56

->

projection : 99 (Krovak)
zone       : 0
datum      : towgs84=570.8,85.7,462.8,4.998,1.587,5.261,3.56

Not sure what formatting is more appropriate.

4) g.region -g X g.region -pg --- I wanted to make -g flag more
universal, e.g. to distinguish

g.region -pcl
g.region -cl

and

g.region -pclg instead of g.region -gcl <-- problem
g.region -gcl <-- problem

The question of the warning in `g.region -g` -- it can be printed at
the end of the output or removed.

5) New lines in shell script style output, I think this modification
can be done in 6.x branch.

These lines can be added to the end of the output for backward
compability -- OK?

Thanks for feedback!

Regards, Martin

2007/1/2, Maciej Sieczka <tutey at o2.pl>:
> Martin Landa wrote:
>
> > 2007/1/2, Maciej Sieczka <tutey at o2.pl>:
> >
> >> "g.region -g" works OK now, but it prints a WARNING message on the top.
> >> It also prints few extra lines, compared to before, namely:
> >>
> >> projection=1
> >> zone=34
> >> datum=wgs84
> >> ellipsoid=wgs84
> >>
> >> Your WARNING message is correct and desired, as well as the extra info
> >>  is usefull, but those several additional lines might brake some user's
> >> scripts.
> >
> > So should I disable this warning, right?
>
> I guess so. But somebody more knowledgable should decide.
>
> > I think the additional lines would not break any scripts, which parse
> > `g.region -g` output in a reasonable way (eval, awk) (?).
>
> Those extra lines might brake all scripts that don't use eval, I
> suppose. Eg. parsing with awk by line number will fail now:
>
> # grab the current region settings
> g.region -g > $TMP.${PROG}.region
>
> # extract variables from the grabbed region
> north=`awk 'BEGIN {FS="="} (NR==1) {print $2}' $TMP.${PROG}.region`
> south=`awk 'BEGIN {FS="="} (NR==2) {print $2}' $TMP.${PROG}.region`
> west=`awk 'BEGIN {FS="="} (NR==3) {print $2}' $TMP.${PROG}.region`
> east=`awk 'BEGIN {FS="="} (NR==4) {print $2}' $TMP.${PROG}.region`
> nsres=`awk 'BEGIN {FS="="} (NR==5) {print $2}' $TMP.${PROG}.region`
> ewres=`awk 'BEGIN {FS="="} (NR==6) {print $2}' $TMP.${PROG}.region`
> rows=`awk 'BEGIN {FS="="} (NR==7) {print $2}' $TMP.${PROG}.region`
> cols=`awk 'BEGIN {FS="="} (NR==8) {print $2}' $TMP.${PROG}.region`
>
> Is that "reasonable" I don't know, but it used to work with g.region -g
> before your recent changes, and now it fails, because top 4 lines of
> g.region -g output are different now.
>
> I personally don't care too much, I have fixed my script to use eval,
> but what with other users?
>
> I absolutely agree you are doing a Good Thing fixing g.region -g as you
> do, but I'm affraid it should wait till GRASS 7, for legacy reasons.
>
> Maciek
>


-- 
Martin Landa <landa.martin at gmail.com> * http://gama.fsv.cvut.cz/~landa *