[GRASS-stats] Loading a point-vector table with 466 columns

[Roger Bivand]

On Sat, 23 May 2009, Hamish wrote:

>
> Roger wrote:
>> Three minutes instead of thirty+ suggests that the OGR
>> plugin has trouble with SQLite as the DB format. So maybe
>> the default for plugin= should be FALSE, not NULL and automatic
>> use if present?
>
> better: if cause for slowdown is isolated (or at least
> reproducable) please file a bug report to get the plugin fixed.
> That way e.g. qgis and others who use the plugin also get the
> speedup.

I'm not running SQLite, nor do I have a "wide" table. Could you, Nikos, 
make a script generating a similar table in spearfish, and two small 
scripts exercising the problem (export to R with the plugin, and with the 
temporary shapefile.

>
>> The plugin also creates a fictitious third dimension in
>> (point at least) data that has created havoc, and has led
>> to readVECT6() getting a pointDropZ= argument - that's why it
>> says that wkbPoint is 3 with the plugin and (correctly) 2
>> otherwise.
>
> ditto.

OK, looks like calls to Vect_is_3d(poMap) missing in 
*OGRGRASSLayer::GetFeatureGeometry about lines after 851 in 
ogf_frmts/grass/ogrgrasslayer.cpp; the problem exists for all geometry 
types, just emitting a z value even if the vect is 2D. I can't see that 
Vect_read_line returns z as NULL if not 3D - Vect_is_3d() is not used much 
in lib/vector/*. I cannot get into the osgeo trac - could you, Hamish, 
help and enter a bug in the GDAL/GRASS or whichever trac stream is 
relevant?

Roger

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> Hamish
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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