Libgis
From RHLUG
libgis is a "Virtual Globe" like library that handles coordinates and the OpenGL viewport. Also provides some generic functionality and a plugin API. It is used by AWeather.
[edit] Architecture
- The View
- The View in libgis refers to a datatype used to store the state of the current viewport, this includes the camera parameters as well as the date and time that is being viewed.
- OpenGL
- The ROAM algorithm is used for generating the mesh used for the earth's surface. A spherical variant is used which starts with 8 triangles arranged in a tetrahedron.
- Primitives
- Libgis provides a variety of primitive drawing structures including:
- Tiles provide support lat-lon images of variable resolution.
- Plugins
- Most functionality is provided by plugins. These should not be confused with "layers" in other virtual globe applications; libgis has no concept of a layer. Plugins are simply a specific type of shared library that can provide arbitrary functionality.
- SRTM - The Shuttle Radar Topography Mission provides elevation data used by ROAM to generate the terrain mesh. It can also generate a greyscale heightmap in place of surface imagry.
- BMNG - The Blue Marble Next Gen plugin provides surface imagery at resolutions up to 500m.
[edit] Screenshots
 The precursor to libgis, libspikeyball |
 Mt. Hood makes for good debugging |
 High level view over Africa |
 Heightmap generated by SRTM data |
 Libgis being used in an application (AWeather) |
