[GRASS-stats] Speedup of readVECT6() with plugin

[Roger Bivand]

On Tue, 24 Jun 2008, Markus Neteler wrote:

> On Tue, Jun 24, 2008 at 12:23 PM, Roger Bivand <Roger.Bivand at nhh.no> wrote:
>> On Mon, 23 Jun 2008, Roger Bivand wrote:
>>
>>> I've submitted spgrass6_0.5-9.tar.gz to CRAN, so barring accidents it
>>> should be out soon. If you're using the raster or vector plugins and have
>>> comments, please let me know - look for the new plugin= argument, which is
>>> FALSE by default to avoid problems, but can be NULL for autodetection, or
>>> TRUE to force use if the plugin is known to be available.
>>
>> My apologies, 0.5-9 was released on CRAN three weeks ago, so no change.
>
> Dear Roger,
>
> not sure what that means: can you upload only periodically from time to 
> time?

No, I just forgot that I had released the package with the changes, and 
tried to release an identical package, but the CRAN administrator asked if 
I was aware of this!

>
>> What I do need is advice on whether to leave plugin=FALSE, or to set
>> plugin=NULL for autodetect, and risk foobars from existing user code
>> assuming the current region rather than the raster region seen by the plugin
>> if installed and autodetected.
>
> Let me suggest:
> The raster plugin behavior will be a problem (we should really fix that in GDAL)
> while the vector plugin behaves well.
> How about having two parameters:
>
> rasterplugin = FALSE
> vectorplugin = NULL
> ?

OK, will do for next release.

>
>> My preference remains for plugin=FALSE, that is, users have to change to
>> NULL or TRUE themselves, and accept the consequences of mixing up regions.
>
> Above might help.
>
>> Is there a shell-level utility in GRASS to check whether the region of a
>> raster is equal to the current working region - the function could call that
>> and create a copy of the required raster in current resolution if they
>> differ?
>
> The easiest way it to compare the output of
>
> r.info -g map127
> north=230000
> south=214000
> east=646000
> west=628000
>
> and
> g.region -g | grep '^n=\|^s=\|^e=\|^w='
> n=228513
> s=214975.5
> w=629992.5
> e=645012

But the resolution may differ too - I need a one shot comparison. Isn't 
anything exposed - I've looked in g.copy and r.resample without seeing 
anything. Maybe:

r.info -gs elevation.dem
g.region -g | grep '^n=\|^s=\|^e=\|^w=\|^ewres=\|^nsres='

but an internal match (where r.resample would be a no-op or not) would be 
helpful.

Roger

>
> Markus
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-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no