posted by admin on Jan 3
GIS Free Open Source product – SAGA GIS
SAGA GIS (System for Automated Geoscientific Analyses) is a free and open source geographic information system used for editing spatial data. It was originally developed by a small team at the Department of Physical Geography, University of Göttingen, Germany, and is now being maintained and extended by an international developer community.
SAGA GIS is a GIS software with the purpose to give (geo-)scientists an effective but easily learnable platform for the implementation of geoscientific methods. This is achieved by the API. SAGA has a fast growing set of geoscientifc methods, bundled in exchangeable Module Libraries.
The standard modules are:
- File access: interfaces to various table, vector, image and grid file formats.
- Filter for grids: Gaussian, Laplacian, multi-directional Lee filter.
- Gridding: interpolation from vector data using triangulation, nearest neighbour, inverse distance.
- Geostatistics: residual analysis, ordinary and universal kriging, single and multiple regression analysis, variance analysis.
- Grid calculator: combine grids through user defined functions.
- Grid discretisation: skeletonisation, segmentation.
- Grid tools: merging, resampling, gap filling.
- Image classification: cluster analysis, box classification, maximum likelihood, pattern recognition, region growing.
- Projections: various coordinate transformations for vector and grid data (using Proj4 and GeoTrans libraries), georeferencing of grids.
- Simulation of dynamic processes: TOPMODEL, nitrogen distributions, erosion, landscape development.
- Terrain analysis: geomorphometrical calculations such as slope, aspect, curvatures, curvature classification, analytical hillshading, sink eliminition, flow path analysis, catchment delineation, solar radiation, channel lines, relative altitudes.
- Vector tools: polygon intersection, contour lines from grid.
SAGA GIS is an effective tool with user friendly GUI that requires only about 10 MB disk space. No installation needed.
Available for Windows and Linux.
SAGA GIS can be used together with other GIS software like Kosmo to get better vector data and map producing capabilities. SAGA GIS modules can be executed from within the statistical data analysis software R in order to integrate statistical and GIS analyses.
SAGA is a Free Open Source Software (FOSS), which generally means that you have the freedom
- to run the program, for any purpose,
- to study how the program works and to modify it,
- to redistribute copies,
- to improve the program, and release the improvements to the public.
Except for the SAGA Application Programming Interface (API) most SAGA source codes have been licenced under the GNU General Public Licence or GPL. The GPL requires derived works to be available under the same or a comparable licence, with other words derived works have to become Open Source as well. For a few reasons the SAGA creators decided to use a less restrictive licence for the SAGA API. The API uses the GNU Lesser General Public Licence or LGPL, which permits use of this library in proprietary programs, i.e. SAGA modules, which always base on the API, have not automatically to be published as Open Source too.
