Sextante
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Introduction
SEXTANTE (Sistema EXTremeño de ANàlisis Territorial) is a library of geoprocesses developed in Java by Victor Olaya. It has more than 280 algorithms that cover many areas within the geospatial analysis, both raster and vector. SEXTANTE is embedded into major opensource GIS projects, such as gvSIG, OpenJUMP or uDig, and in free/propetary non-java projects like QGIS and ArcGIS. Sextante is distributed with OpenJUMP PLUS version
Documentation
The following documents (PDF, in English) are available on OpenJUMP web site:
- Introduction to Sextante. A complete manual of all the functions available on Sextante.
- Sextante Programming Guide. How to program a Sextante plugin
- Sextante List of Algorithms. The complete list of Algorithms available on OpenJUMP Sextante
Other on-line documents
- Evaluation of gvSIG and SEXTANTE Tools for Hydrological Analysis Schröder Dietrich, Mudogah Hildah and Franz David. 6th International gvSIG Conference. PDF
- Using SEXTANTE from the console. This web page comes from QGIS 1.8 documentation and it might work for OpenJUMP SExtante.
Wiki documentation related on Sextante Raster management in OpenJUMP
Programming section
- Example Plugin For Accessing Sextante Algorithms
- How to load a Sextante raster layer and read its cell values
There is also a YouTube channel (SEXTANTE Geo-spatial Library) on how to use Sextante.
A well done documentation is also provided via Sextante>Sextante help context menu as HTML files
OpenJUMP and Sextante
Since OpenJUMP version 1.4.1 Sextante has been embedded into the PLUS version. Sextante can easily work with vectors layer loaded via File>Open>File file chooser. To work with raster files, those must be loaded using 'File>Open>Sextante Raster Image' option. Current supported image formats are ASC FLT GIF JPG PNG TIF.
Examples of Sextante Raster Algorithms
The following tables show some algorithms for Raster analysis, referring to analogous in ArcGIS Spatial Analyst
| Spatial Analyst (menu) | Sextante (menu) |
|---|---|
| Slope, Aspect, Real area, Curvature (Terrain Analysis) | Slope, Aspect, Real area, Curvature (Geomorphometry and Terrain analysis) |
| Viewshed (Terrain Analysis) | Visibility (Visibility and Lightning) |
| Hillshade (Terrain Analysis) | Shaded relief (Visibility and Lightning) |
| Zonal Statistics (Zonal) | Grid Statistics in polygons (Tools for polygons) |
| Sample (Extraction toolset) | Sample raster layer (Tools for points) |
| Extract by polygon (Extraction toolset) | Crop raster with polygon layer (Basic tools for raster layers) |
| IDW, Krigin, Natural Neighbuor (Interpolation toolset) | IDW, Krigin, Nearest Neighbour (Rasterization and interpolation) |
| Vector to raster menu | Rasterization and interpolation menu |
| Reclass toolset and Map Algebra toolsets | Reclassify raster layer menu |
| Hidrology toolset | Basic hydrological analisys |
How to use Sextante Modeler
- Open Sextante Modeler
- Build the model and save it.
- Close Sextante Modeler
- Open Sextante Toolbox. It will show the new model into the tree under Models – Models
- Double click the model – Run
The folder where models are saved can be changed through Sextante settings –Models – Models folder.
Technical notes
- OpenJUMP Sextante binding is the file ojsextante_binding_XXX.jar (where XXX is the date of build) located into OpenJUMP/lib/ext folder
- the core of Sextante software are the files: sextante.jar, sextante_gui.jar and sextante_algorithms.jar located into OpenJUMP/lib/ext/sextante folder
- There are other files located into ext/sextante folder which are needed as external libraries by sextante, such as jfreechart and common.
- Source code of Sextante is stored by GvSIG CE repository
- Source code of OpenJUMP Sextante binding is stored in The JUMP Pilot Project