[R-sig-Geo] suggestion for spgrass6 - temp file in readVECT6

Dylan Beaudette debeaudette at ucdavis.edu
Thu Dec 9 22:31:44 CET 2010

On Thursday, December 09, 2010, Pierre Roudier wrote:
> Dear all,
> I got a suggestion for spgrass6. As far as I understand it, a
> temporary ESRI shapefile is written on the disk when using
> readVECT6('foo'), I guess then R is using rgdal to read that shapefile
> back in memory. Considering the various limitations of the ESRI
> shapefile format that does not occur with the GRASS internal format,
> could it be possible to add an option to choose the OGR format used in
> that process?
> Also got a question for Roger I guess: I'm using now the grass7 svn
> trunk, should I expect any problems using the spgrass6 interface (I
> mean problems due to structural differences that appears in grass7
> that would not be handled by spgrass6, not problems due to grass7
> itself).
> Thanks,
> Pierre

This is an excellent point Pierre, and something that has caused significant 
pain the past-- in terms of column names and NULL value handling. Not 
everyone's GDAL/OGR will be configured in the same way-- so I don't know if 
altering the default behavior would be wise. However, adding an option (as you 
suggested) to use some other format, such as SQLite, would give power users a 
nice alternative to SHP format. SQLite would allow for longer field names, 
proper support for NULL data, and probably some other 'good things'.


Dylan Beaudette
Soil Resource Laboratory
University of California at Davis

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