Cool... I think that one way around the "slow union" problem is to develop a "Cascading Union" function. This will build up a union of multiple geometries by forming them into a tree, and recursively unioning the branches of the tree from the leaves to the root. In theory this should provide a fairly optimal balance between performance and memory use.
A nice way to form the tree would be to add the input geometries to a JTS Quadtree or STRtree and then traverse the tree in depth-first order. Unfortunately currently the implementations don't support the ability to traverse the tree in any order - this wouldn't be too hard to add, though. Thoughts? Anyone keen on trying this out? Martin Larry Becker wrote: > I have committed the improved buffer plugin. Three sample screens are > attached in english, french, and german. It now supports buffering > the selection. It provides a convenience union option. The sidebar > picture now previews the current options. It copies attributes by > default, even from selections on multiple layers, but this can be > turned off. It supports setting the number of segments in a quarter > circle. > > Be careful with the union operation. With large selections, it can > take a long time. For instance using Uwe's GeoCity project, I tried > to buffer everything by 1000 meters. Without union it completed in > about 20 seconds, and with union I finally killed it after 5 minutes. > > regards, > Larry Becker > > > ------------------------------------------------------------------------ > > > ------------------------------------------------------------------------ > > > ------------------------------------------------------------------------ > > ------------------------------------------------------------------------ > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > ------------------------------------------------------------------------ > > _______________________________________________ > Jump-pilot-devel mailing list > Jump-pilot-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel > -- Martin Davis Senior Technical Architect Refractions Research, Inc. (250) 383-3022 ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Jump-pilot-devel mailing list Jump-pilot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel
