Hi all, Roberto Rossi and I made a revision on Rasterize vector layer tools in OpenJUMP. This functionality is quite essential in raster analysis as it allows to transfer info in a raster to reuse in so-called Raster algebra to get new information. Generally, in a raster analysis, the number of vector files that can be transformed into rasters can be huge. So the user needs a fast and exact rasterization tool
OpenJUMP currently has two tools: one on sextante toolbox and the other on OpenKLEM plugin. a) The one of OpenKLEM is quite exact on transformation but it takes a quite long time to convert a vector file to a raster. In a test, using a layer with 6000 polygons, this tool takes almost 4 to 5 minutes. It is not acceptable if the user needs to convert many layers. b) The tool in Sextante is very fast, basically 6 to 7 seconds for a layer of 6000 polygons. The problem of this tool is that it requires that the vector layer should be first validated to correct non simple geometries and then the geometries must be merged according to common values from an attribute name. The second (merge) is sequential to the first (validate). All those three processes (Validate, Merge and Rasterize) are located into different plugins between OJ and Sextante. Using all to rasterize a vector will enlarge the time and actions and it will again not be acceptable if the files to convert are many. In order to solve this problem, I developed a Raterization plugin for OpenJUMP, mostly reusing Sextante code but adding also the other preprocesses (Validate and Merge). This plugin shows a relatively short time to do all the process until rasterization (10 to 12 seconds). I will add this plugin in the next days after doing some cleaning of code Best regards Peppe
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