OpenJUMP is an open source GIS software written in Java. It is based on JUMP GIS by Vivid Solutions.
It is a Vector GIS that can read rasters as well. It is not just another free demo viewer, but you can edit, save, analyze etc. with OpenJUMP. It works, even with medium size datasets, and with professional touc. It provides a GIS API with a flexible plugin structure, so that new features are relatively easy to develope around the sound mapping platform. It utilises standards like GML, WMS and WFS. It is already translated in several languages.
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