[R-sig-Geo] Editing Shapefiles, and cartograms

[Nicholas Lewin-Koh]

Hi,
In the days when I had more time to work on this stuff I looked into
programming continuous cartograms for maptools. If I remember correctly
Danny Dorlings 
approach produced really nicely arranged circualr cartograms. I also
remember
that the optimization he used was fairly inefficient and could take a
looooong time
if you had many polygons. I think there is a note in Jason Dyke's CDV
software about that.
I think the speed of Dorling's algorithm could be much improved with the
application
of a little computational geometry, but like I said it is a few years
since I looked at this.

As far as interactivity, iplots is one solution. I played with trying to
embed cdv in R
using the tcltk interface, but it wasn't as well developed as it is now,
and I am not a good
tcltk programmer. Another thing I tried was embedding ggobi in openEV,
Frank Warmerdam's map
viewing tool. That approach seemed to have promise, and openEV plays
nicely with other languages.

Cheers
Nicholas