 # Rugged > A sensor-to-terrain mapping tool [Rugged](www.orekit.org/rugged/ "Rugged homepage") is a free java library for geolocation and used for satellite imagery. Rugged is an add-on for [Orekit](https://www.orekit.org/ "Orekit homepage") handling Digital Elevation Models contribution to line of sight computation. It is a free software intermediate-level library written in Java. It mainly provides direct and inverse location, i.e. it allows to compute accurately which ground point is looked at from a specific pixel in a spacecraft instrument, and conversely which pixel will see a specified ground point. This mapping between ground and sensor is computed with a viewing model taking into account: * ground Digital Elevation Model (DEM), * Earth rotation will all its tiny irregularities, * on-board sensor pixels individual line-of-sights, * spacecraft motion and attitude, * several physical effects. Direct and inverse location can be used to perform full ortho-rectification of images and correlation between sensors observing the same area. [](https://sonar.orekit.org/dashboard?id=org.orekit%3Arugged) [](https://sonar.orekit.org/dashboard?id=org.orekit%3Arugged) ## Download ### Official releases [Official Rugged releases](https://gitlab.orekit.org/orekit/rugged/-/releases) are available on our [Gitlab instance](https://gitlab.orekit.org/). They are also available in the [Maven repository](https://mvnrepository.com/artifact/org.orekit/rugged). ### Development version To get the latest development version, please clone our official repository and checkout the `develop` branch: ```bash git clone -b develop https://gitlab.orekit.org/orekit/rugged.git ``` __Note:__ Our official repository is [mirrored on Github](https://github.com/CS-SI/Rugged). ## Documentation Project overview, architecture and development, detailed features list, Javadoc and a lot of other information is available on the [Maven site](https://www.orekit.org/site-rugged-development/). ## Getting help The main communication channel is our [forum](https://forum.orekit.org/). You can report bugs and suggest new features in our [issues tracking system](https://gitlab.orekit.org/orekit/rugged/-/issues). When reporting security issues check the "This issue is confidential" box. ## Contributing Please take a look at our [contributing guidelines](https://www.orekit.org/site-rugged-latest/contributing.html) if you're interested in helping! ## Building Detailed information on how to build Rugged from source either using Maven or Eclipse is provided in [building](https://www.orekit.org/site-rugged-latest/building.html) explanations. ## Dependencies Rugged relies on the following [FOSS](https://en.wikipedia.org/wiki/Free_and_open-source_software) libraries, all released under business friendly FOSS licenses. ### Compile-time/run-time dependencies * [Orekit](https://www.orekit.org/), a low level space dynamics library released under the Apache License, version 2.0. * [Hipparchus](https://hipparchus.org/), a mathematics library released under the Apache License, version 2.0. ### Test-time dependencies * [JUnit 4](http://www.junit.org/), a widely used unit test framework released under the Eclipse Public License, version 1.0. More detailed information is available in the [Maven site](https://www.orekit.org/site-rugged-development/dependencies.html). ## License Rugged is licensed by [CS GROUP](https://www.c-s.fr/) under the [Apache License, version 2.0](http://www.apache.org/licenses/LICENSE-2.0.html). A copy of this license is provided in the [LICENSE.txt](LICENSE.txt) file.