Dear Luke & others, Congratulations on getting this library as far as a review. I feared that the scope of the subject might make it impossible for anyone to ever get this far. Perhaps we have Luke's employer to thank for this. I hope to have time to try out the library with at least a couple of real-world examples. I'll describe the problems that I have in mind now and update later with my experiences. Marker Merging: I have lots of small square markers indicating search results on a map. If the map is zoomed out so that the whole planet is visible and you search for something common like "lake", it will attempt to draw many thousands of overlapping markers which is slow. Since the markers are just squares of solid colour, I would like to merge them into a single polygon-set and plot that. Speed is the main concern. It it also interesting to consider what would happen if the markers were circles. Here's an example of the sort of output I need: http://chezphil.org/tmp/six_thousand_lakes.jpeg Border Simplification: I have data describing state outlines as polygon-sets. I want to pre-process that into a format that permits rapid rendering; specifically, I want to generate multi-resolution versions with smoothing and interpolation as necessary. I also want to reduce it from polygons with common edges to polylines, so that each border is plotted once rather than twice. This is something that happens off-line as part of a build process, so speed is much less important than ease of coding. Example output: http://chezphil.org/tmp/state_borders.jpeg (yes, it's an iPhone app... hey, we all have to pay the rent somehow...) Regards, Phil. p.s. has anyone worked out where this thread has gone on gmane.org?