Pycnophylactic Interpolation Given a SpatialPolygonsDataFrame and a set of populations for each polygon, compute a population density estimate based on Tobler's pycnophylactic interpolation algorithm. The result is a SpatialGridDataFrame. Software Depends: stats, sp, maptools, rgeos Chris Briunsdon <cb179@le.ac.uk> Chris Brunsdon GPL (>= 2) 2011-06-17 application/tgz http://CRAN.R-project.org/package=pycno