[R-sig-Geo] Re: [R] writing polygons/segments to shapefiles(.shp)or other A rcGIS compatible file

[Nicholas Lewin-Koh]

Hi Roger,
Just working on it now. Just created an empty shapefile from R
complete with segmentation fault :)
debugging it now.

I think the code in shapelib, shprewind, is an example of using 
the shapelib api to do shape checking. I will follow this up further.
meanwhile i will work on getting something started.

Nicholas



On Tue, 2 Mar 2004 15:42:39 +0100 (CET), "Roger Bivand"
<Roger.Bivand at nhh.no> said:
> On Mon, 1 Mar 2004, Nicholas Lewin-Koh wrote:
> 
> > Hi again,
> > I took a look at maptools code and shapelib last night. It should not be
> > hard to modify to create and write 
> > shapefiles. I think I never developed it in maptools because I never
> > really thought of R as
> > being suitable for editing maps. I thought R would be very suitable for
> > designing cartographic dispays for 
> > statistical purposes. 
> 
> I think you are correct in principle, but I can see situations where 
> people want to export subsets of say polygons, lines, or points.
> 
> > 
> > That said, If I can get it working in an evening or two I will submit it
> > to Roger for inclusion in maptools.
> 
> That's very generous - if you can make a first attempt at making your
> code 
> work, that will give us a start. The places where my head ached were 
> whether we need to check shapes for compliance before writing them to
> file 
> - but maybe shapelib does that - I don't think so? Should we just let 
> people write anyway?
> 
> 
> > Do any of the other geo interfaces in development write map formats? Eg
> > the Rgdal interface?
> > 
> 
> It should but doesn't - you can (I think) overwrite bands, but this is 
> something that needs fixing - for those interested, rgdal is on 
> sourceforge, so checking out under cvs is possible, so that improvements 
> and additions can be brought in under control.
> 
> Roger
> 
> > Nicholas
> > 
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> > 
> 
> -- 
> Roger Bivand
> Economic Geography Section, Department of Economics, Norwegian School of
> Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
> Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
> e-mail: Roger.Bivand at nhh.no
> 
>