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

[Roger Bivand]

On Sun, 1 Jun 2008, Markus Neteler wrote:

> On Sun, Jun 1, 2008 at 8:47 PM, Roger Bivand <Roger.Bivand at nhh.no> wrote:
>> On Sat, 31 May 2008, Markus Neteler wrote:
>>> On Sat, May 31, 2008 at 6:35 PM, Roger Bivand <Roger.Bivand at nhh.no> wrote:
>>>> On Sat, 31 May 2008, Markus Neteler wrote:
>>>>> On Sat, May 31, 2008 at 5:51 PM, Roger Bivand <Roger.Bivand at nhh.no> wrote:
>>>>>> On Sat, 31 May 2008, Markus Neteler wrote:
>>>>>>>
>>>>>>> I have to read in Lidar data from GRASS, so speed matters. I have
>>>>>>> modified the readVECT6() function to not export to SHAPE but
>>>>>>> read in directly via GRASS-GDAL/OGR plugin:
> ...
>> The SELinux was a red herring, I simply hadn't understood the change in
>> plugin technology. The current CVS version works for me on F7 under SELinux
>> with the plugin built as described in the wiki.
>>
>> Please try the CVS version at:
>>
>> cvs -d:pserver:anonymous at r-spatial.cvs.sourceforge.net:/cvsroot/r-spatial login
>>
>> cvs -z3 -d:pserver:anonymous at r-spatial.cvs.sourceforge.net:/cvsroot/r-spatial co -P spgrass6
>
>
> Dear Roger,
>
> thanks for the high speed rewrite of the interface. Downloaded and installed
> successfully (I see the new message
> "GRASS GIS interface loaded with GRASS version: 6.4.svn"
> ).
>
>> or a variant that works. The vector version looks OK,
>
> I have made the test again but cannot observe a speed improvement.
> I guess I have to debug it somehow.

Markus,

For now, the plugin= argument defaults to FALSE. If NULL, it will 
autodetect, if TRUE, it will try to use the plugin or fail. To avoid 
breaking things for users with a plugin but scripts that might break, I 
set plugin=FALSE for now. Once we have some experience, I'll increment the 
version number from 0.5-* to 0.6-1, and set plugin=NULL by default.

Roger

>
>> the raster version is
>> basic (uses data resolution not window resolution, and only handles one
>> raster at a time without categories).
>
> AFAIK the plugin delivers only *original* raster resolution and extent (that's
> why r.out.gdal was written in C to replace a former plugin based shell script).
> So, unless the plugin is changed here it might not be that useful for raster
> data *if* the GRASS behaviour of respecting raster settings during export
> should be maintained.
>
> thanks,
> Markus
>

-- 
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