[R-sig-Geo] Editing Shapefiles

[Roger Bivand]

On Wed, 14 Dec 2005, Susumu Tanimura wrote:

> Dear Rick Reeves and members
> 
> > But ne question: where is the polycoords() method defined? I can't find 
> > it...
> 
> I guess it come from Rmap package.  You may use Rmap or write a same
> function with maptools.

Yes, it is a method in Rmap defined for ogr and shapefile data sources. It 
returns a list with matrices of coordinates, split by NA rows between 
parts of the entity.

A lot of the good ideas in Rmap are continued in the sp package, which 
tries to split data input from the objects themselves and methods for 
handling objects.

The work on Susumu Tanimura's web pages is magnificent, really very 
useful, and I agree completely with Nicholas that it will be very useful 
to make it available to others through packages on CRAN.

> 
> As for cartogram, I have rewritten the cartogram code in accordance
> with maptools, I lost it though.

Some time ago, Danny Dorling gave me his cartogram code. It does, however, 
require boundary proportions for contiguous neighbours - which means that 
a full topology has to be available. We can do that either using GRASS 
(Markus Neteler helped to show how, I still have to write it up), or using 
information in ArcInfo coverages or e00 files read through RArcInfo. That 
would give bubble cartograms, if someone would like to try it out?

Roger


> 
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo at stat.math.ethz.ch
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> 

-- 
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