SAGA GIS
System for Automated Geoscientific Analyses (SAGA GIS) is a geographic information system (GIS) computer program, used to edit spatial data. It is free and open-source software, developed originally 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 intended to give scientists an effective but easily learnable platform for implementing geoscientific methods. This is achieved by the application programming interface (API). SAGA has a fast-growing set of geoscientific methods, bundled in exchangeable module libraries. The standard modules are: File access: interfaces to various table, vector, image and grid file formats, including shapefiles, Esri grids (ASCII and binary), and many grid file formats supported by the Geospatial Data Abstraction Library (GDAL), along with the native SGRD format of SAGA GIS. 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