Dear all

In using Natureserve's birdlife maps, I get the following message with the current version of PBSmapping 2.66.53. This apparently only happens when there is no intersection:

joinPolys(SpatialPolygons2PolySet(ranges[[1]]), SpatialPolygons2PolySet(ranges[[2]]), operation="INT")

Error in if (nrow(results) > 0) { : argument is of length zero

The operation worked fine with version 2.63.37 and perhaps there is some simple way to fix it?

In addition, I wonder if there are other ways suggested to get the intersection?    gIntersection in rgeos doesn't work well, because quite a few of the geometries on Natureserve are not valid according to rgeos criteria.

I am unsure if I should post a couple of geometries up, and how best to do that.

many thanks
Trevor

Trevor Price
Department of Ecology and Evolution
University of Chicago

773-702-5176

########################
Become Carbon neutral today
Visit: www.savingspecies.org
########################


	[[alternative HTML version deleted]]

