WorldPainter
WorldPainter is an interactive map generator for Minecraft. It allows you to "paint" landscapes using similar tools as a regular paint program. Sculpt and mould the terrain, paint materials, trees, snow and ice, etc. onto it, and much more.
Distributing
WorldPainter is open source software, licensed under the GPL version 3. This means that if you distribute it, original or in modified form, you must also distribute it (including your changes) as open source under the GPL version 3 (or later). See the LICENSE file for details.
Building
WorldPainter is a Maven project and easy to build from the command line with Maven, or using your favourite IDE. However there are some missing dependencies which are not in Maven Central which you will have to install locally first. See the BUILDING file for details.