GRASS GIS is a fully featured Geographic Information System. It supports raster, vector and point data analysis.

GRASS accepts a variety of raster and some vector dataformats - most of the raster formats are equal to standard image formats (8/24 bit as well as negative values). Check the documentation for details. The following table shows an overview of the features integrated in GRASS GIS.

What are the main capabilities of GRASS 4.3?

Main topic

Modules
Raster analysis
Automatic rasterline and area to vector conversion

Buffering of line structures

Cell and profile dataquery

Colortable modifications

Conversion to vector and point data format

Correlation / covariance analysis

Expert system analysis

Interpolation for missing values

Neighbourhood matrix analysis

Raster overlay with or without weight

Reclassification of cell labels

Resampling (resolution)

Rescaling of cell values

Statistical cell analysis

Surface generation from vector lines
Vector analysis
Contour generation from rastersurface

Conversion to raster and point data format

Digitizing with board or on screen (scanned rasterimage) with mouse

Reclassification of vector labels

Superpositioning of vector layers
Point data analysis
Delaunay triangulation

Surface interpolation from spot heights

Thiessen polygons

Topographic analysis (curvature, slope, aspect)
Image processing
Canonial component analysis (CCA)

Color composite generation

Edge detection

Frequency filtering (Fourier, convolution matrices)

Fourier and inverse fourier transformation

Histogram stretching

IHS transformation to RGB

Image rectification (affine and polynomial transformations on raster and vector targets)

Ortho photo rectification

Principal component analysis (PCA)

Radiometric corrections (Fourier)

Resampling

Resolution enhancement (with RGB/IHS)

RGB to IHS transformation

Texture oriented classification (sequential maximum a posteriori classification)

Shape detection

Supervised classification (training areas, maximum likelyhood classification)

Unsupervised classification (minimum distance clustering, maximum likelyhood classification)
DTM-Analysis
Contour generation

Cost / path analysis

Slope / aspect analysis

Surface generation from spot heigths or contours
Screen displaying
3D surfaces

Color assignments

Histogram presentation

Map overlay

Point data maps

Raster maps

Vector maps

Zoom / unzoom -function
Map creation
PPM-image maps

Postscript maps
Extra modules
Database interfaces (Informix, Ingres, PostgreSQL)
(several other modules are available)
Erosion modelling (AGNPS, ANSWERS)

Landscape structure analysis

Solution transport

Watershed analysis