Author: GRASS Development Team

## GRASS GIS 6.2.3 Reference Manual

Geographic Resources Analysis Support System, commonly referred to as GRASS, is a Geographic Information System (GIS) used for geospatial data management and analysis, image processing, graphics/maps production, spatial modeling, and visualization. GRASS is currently used in academic and commercial settings around the world, as well as by many governmental agencies and environmental consulting companies.

This reference manual details the use of modules distributed with Geographic Resources Analysis Support System (GRASS), an open source (GNU GPL'ed), image processing and geographic information system (GIS).

### Quick Introduction

- GRASS startup manual page
- How to start with GRASS
- Introductions
  - 2D raster map processing
  - 3D raster map (voxel) processing
  - Image processing
  - Database management
  - Vector map processing and network analysis
  - Projections and spatial transformations
  - SQL support
  - Display drivers
  - GRASS variables and environment variables
- The GRASS Extensions Manager (GEM)

imagery commands:

i.cca | Canonical components analysis (cca) program for image processing.
i.class | i.class
i.cluster | An imagery function that generates spectral signatures for land cover types in an image using a clustering algorithm. The resulting signature file is used as input for i.maxlik, to generate an unsupervised image classification.
i.fft | Fast Fourier Transform (FFT) for image processing.
i.fusion.brovey | Brovey transform to merge multispectral and high-res panchromatic channels
i.gensig | Generates statistics for i.maxlik from raster map layer.
i.gensigset | Generate statistics for i.smap from raster map layer.
i.group | Creates and edits groups and subgroups of imagery files.
i.his.rgb | Hue-intensity-saturation (his) to red-green-blue (rgb) raster map color transformation function.
i.ifft | Inverse Fast Fourier Transform (ifft) for image processing.
i.image.mosaic | Mosaics up to 4 images and extends colormap; creates map *.mosaic
i.in.spotvgt | Import of SPOT VGT NDVI file into a raster map
i.landsat.rgb | Auto-balancing of colors for LANDSAT images
i.maxlik | An imagery function that classifies the cell spectral reflectances in imagery data based on the spectral signature information generated by either i.cluster, i.class, or i.gensig.
i.oif | Calculates Optimum-Index-Factor table for LANDSAT TM bands 1-5, & 7
i.ortho.photo | i.ortho.photo
i.pca | Principal components analysis (pca) program for image processing.
i.points | Mark ground control points on image to be rectified.
i.rectify | Rectifies an image by computing a coordinate transformation for each pixel in the image based on the control points
i.rgb.his | Red-green-blue (rgb) to hue-intensity-saturation (his) raster map color transformation function.
i.smap | Performs contextual image classification using sequential maximum a posteriori (SMAP) estimation.
i.spectral | displays spectral response at user specified locations in group or images
i.target | Targets an imagery group to a GRASS location and mapset.
i.tasscap | Tasseled Cap (Kauth Thomas) transformation for LANDSAT-TM data
i.vpoints | Set registration points for an imagery group from a vector map or keyboard entry.
i.zc | Zero-crossing "edge detection" raster function for image processing.

Help Index | Full Index
© 2003-2007 GRASS Development Team