[GRASS-dev] GRASS 7: d.vect: layer=-1 default conflicts with
where option
Glynn Clements
glynn at gclements.plus.com
Tue Sep 6 01:20:35 EDT 2011
Markus Neteler wrote:
> > Making it support where= with all layers would require a substantial
> > re-write (and requires that you can come up with a single query which
> > works for all layers).
>
> Sure but what I meant to say:
>
> d.vect mylakes where="FTYPE IS NULL" type=area col=red
>
> ... this works in GRASS 6
... even if the map has multiple layers. This should be considered a
bug in 6.x, IMHO.
> and fails in GRASS 7 since the default
> layer value is unsuitable. IMHO default values should work (as before).
Is layer 1 *genuinely* special? I.e. is there some reason why it
*should* be the default layer?
As it stands, the default behaviour of d.vect in 6.x is to display
*some* data without any indication that it isn't displaying all of it.
I can see an argument for silently selecting layer 1 *if* a map only
has one layer, although this is practically asking for people to write
scripts which can't be used on maps with more than one layer.
If a map has multiple layers, where= is given, and layer= is not
given, then an error seem preferable to silently producing
"incomplete" output.
--
Glynn Clements <glynn at gclements.plus.com>
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