GRASS GIS 7.8.6 Reference Manual

Geographic Resources Analysis Support System, commonly referred to as GRASS GIS, 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 GPLed), image processing and geographic information system (GIS). Go to raster introduction | topics

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Raster commands:

r.basins.fill		Generates watershed subbasins raster map.
r.blend		Blends color components of two raster maps by a given ratio.
r.buffer		Creates a raster map showing buffer zones surrounding cells that contain non-NULL category values.
r.buffer.lowmem		Creates a raster map showing buffer zones surrounding cells that contain non-NULL category values.
r.buildvrt		Build a VRT (Virtual Raster) from the list of input raster maps.
r.carve		Generates stream channels.
r.category		Manages category values and labels associated with user-specified raster map layers.
r.circle		Creates a raster map containing concentric rings around a given point.
r.clump		Recategorizes data in a raster map by grouping cells that form physically discrete areas into unique categories.
r.coin		Tabulates the mutual occurrence (coincidence) of categories for two raster map layers.
r.colors		Creates/modifies the color table associated with a raster map.
r.colors.out		Exports the color table associated with a raster map.
r.colors.stddev		Sets color rules based on stddev from a raster map’s mean value.
r.composite		Combines red, green and blue raster maps into a single composite raster map.
r.compress		Compresses and decompresses raster maps.
r.contour		Produces a vector map of specified contours from a raster map.
r.cost		Creates a raster map showing the cumulative cost of moving between different geographic locations on an input raster map whose cell category values represent cost.
r.covar		Outputs a covariance/correlation matrix for user-specified raster map layer(s).
r.cross		Creates a cross product of the category values from multiple raster map layers.
r.describe		Prints terse list of category values found in a raster map layer.
r.distance		Locates the closest points between objects in two raster maps.
r.drain		Traces a flow through an elevation model or cost surface on a raster map.
r.external		Links GDAL supported raster data as a pseudo GRASS raster map.
r.external.out		Redirects raster output to file utilizing GDAL library rather than storing in GRASS raster format.
r.fill.dir		Filters and generates a depressionless elevation map and a flow direction map from a given elevation raster map.
r.fill.stats		Rapidly fills ’no data’ cells (NULLs) of a raster map with interpolated values (IDW).
r.fillnulls		Fills no-data areas in raster maps using spline interpolation.
r.flow		Constructs flowlines.
r.geomorphon		Calculates geomorphons (terrain forms) and associated geometry using machine vision approach.
r.grow.distance		Generates a raster map containing distances to nearest raster features and/or the value of the nearest non-null cell.
r.grow		Generates a raster map layer with contiguous areas grown by one cell.
r.gwflow		Numerical calculation program for transient, confined and unconfined groundwater flow in two dimensions.
r.his		Generates red, green and blue (RGB) raster map layers combining hue, intensity and saturation (HIS) values from user-specified input raster map layers.
r.horizon		Computes horizon angle height from a digital elevation model.
r.import		Imports raster data into a GRASS raster map using GDAL library and reprojects on the fly.
r.in.ascii		Converts a GRASS ASCII raster file to binary raster map.
r.in.aster		Georeference, rectify, and import Terra-ASTER imagery and relative DEMs using gdalwarp.
r.in.bin		Import a binary raster file into a GRASS raster map layer.
r.in.gdal		Imports raster data into a GRASS raster map using GDAL library.
r.in.gridatb		Imports GRIDATB.FOR map file (TOPMODEL) into a GRASS raster map.
r.in.lidar		Creates a raster map from LAS LiDAR points using univariate statistics.
r.in.mat		Imports a binary MAT-File(v4) to a GRASS raster.
r.in.png		Imports non-georeferenced PNG format image.
r.in.poly		Creates raster maps from ASCII polygon/line/point data files.
r.in.srtm		Imports SRTM HGT files into raster map.
r.in.wms		Downloads and imports data from OGC WMS and OGC WMTS web mapping servers.
r.in.xyz		Creates a raster map from an assemblage of many coordinates using univariate statistics.
r.info		Outputs basic information about a raster map.
r.kappa		Calculates error matrix and kappa parameter for accuracy assessment of classification result.
r.lake		Fills lake at given point to given level.
r.latlong		Creates a latitude/longitude raster map.
r.li.cwed		Calculates contrast weighted edge density index on a raster map
r.li.daemon		Support module for r.li landscape index calculations.
r.li.dominance		Calculates dominance’s diversity index on a raster map
r.li.edgedensity		Calculates edge density index on a raster map, using a 4 neighbour algorithm
r.li		Toolset for multiscale analysis of landscape structure
r.li.mpa		Calculates mean pixel attribute index on a raster map
r.li.mps		Calculates mean patch size index on a raster map, using a 4 neighbour algorithm
r.li.padcv		Calculates coefficient of variation of patch area on a raster map
r.li.padrange		Calculates range of patch area size on a raster map
r.li.padsd		Calculates standard deviation of patch area a raster map
r.li.patchdensity		Calculates patch density index on a raster map, using a 4 neighbour algorithm
r.li.patchnum		Calculates patch number index on a raster map, using a 4 neighbour algorithm.
r.li.pielou		Calculates Pielou’s diversity index on a raster map
r.li.renyi		Calculates Renyi’s diversity index on a raster map
r.li.richness		Calculates richness index on a raster map
r.li.shannon		Calculates Shannon’s diversity index on a raster map
r.li.shape		Calculates shape index on a raster map
r.li.simpson		Calculates Simpson’s diversity index on a raster map
r.mapcalc		Raster map calculator.
r.mapcalc.simple		Calculates a new raster map from a simple r.mapcalc expression.
r.mask		Creates a MASK for limiting raster operation.
r.mfilter		Performs raster map matrix filter.
r.mode		Finds the mode of values in a cover map within areas assigned the same category value in a user-specified base map.
r.neighbors		Makes each cell category value a function of the category values assigned to the cells around it, and stores new cell values in an output raster map layer.
r.null		Manages NULL-values of given raster map.
r.out.ascii		Converts a raster map layer into a GRASS ASCII text file.
r.out.bin		Exports a GRASS raster to a binary array.
r.out.gdal		Exports GRASS raster maps into GDAL supported formats.
r.out.gridatb		Exports GRASS raster map to GRIDATB.FOR map file (TOPMODEL).
r.out.mat		Exports a GRASS raster to a binary MAT-File.
r.out.mpeg		Converts raster map series to MPEG movie.
r.out.png		Export a GRASS raster map as a non-georeferenced PNG image.
r.out.pov		Converts a raster map layer into a height-field file for POV-Ray.
r.out.ppm		Converts a GRASS raster map to a PPM image file.
r.out.ppm3		Converts 3 GRASS raster layers (R,G,B) to a PPM image file.
r.out.vrml		Exports a raster map to the Virtual Reality Modeling Language (VRML).
r.out.vtk		Converts raster maps into the VTK-ASCII format.
r.out.xyz		Exports a raster map to a text file as x,y,z values based on cell centers.
r.pack		Exports a raster map as GRASS GIS specific archive file
r.param.scale		Extracts terrain parameters from a DEM.
r.patch		Creates a composite raster map layer by using known category values from one (or more) map layer(s) to fill in areas of "no data" in another map layer.
r.path		Traces paths from starting points following input directions.
r.plane		Creates raster plane map given dip (inclination), aspect (azimuth) and one point.
r.profile		Outputs the raster map layer values lying on user-defined line(s).
r.proj		Re-projects a raster map from given location to the current location.
r.quant		Produces the quantization file for a floating-point map.
r.quantile		Compute quantiles using two passes.
r.random.cells		Generates random cell values with spatial dependence.
r.random		Creates a raster map layer and vector point map containing randomly located points.
r.random.surface		Generates random surface(s) with spatial dependence.
r.reclass.area		Reclasses a raster map greater or less than user specified area size (in hectares).
r.reclass		Reclassify raster map based on category values.
r.recode		Recodes categorical raster maps.
r.region		Sets the boundary definitions for a raster map.
r.regression.line		Calculates linear regression from two raster maps: y = a + b*x.
r.regression.multi		Calculates multiple linear regression from raster maps.
r.relief		Creates shaded relief map from an elevation map (DEM).
r.report		Reports statistics for raster maps.
r.resamp.bspline		Performs bilinear or bicubic spline interpolation with Tykhonov regularization.
r.resamp.filter		Resamples raster map layers using an analytic kernel.
r.resamp.interp		Resamples raster map to a finer grid using interpolation.
r.resamp.rst		Reinterpolates and optionally computes topographic analysis from input raster map to a new raster map (possibly with different resolution) using regularized spline with tension and smoothing.
r.resamp.stats		Resamples raster map layers to a coarser grid using aggregation.
r.resample		GRASS raster map layer data resampling capability.
r.rescale.eq		Rescales histogram equalized the range of category values in a raster map layer.
r.rescale		Rescales the range of category values in a raster map layer.
r.rgb		Splits a raster map into red, green and blue maps.
r.ros		Generates rate of spread raster maps.
r.series.accumulate		Makes each output cell value a accumulationfunction of the values assigned to the corresponding cells in the input raster map layers.
r.series		Makes each output cell value a function of the values assigned to the corresponding cells in the input raster map layers.
r.series.interp		Interpolates raster maps located (temporal or spatial) in between input raster maps at specific sampling positions.
r.shade		Drapes a color raster over an shaded relief or aspect map.
r.sim.sediment		Sediment transport and erosion/deposition simulation using path sampling method (SIMWE).
r.sim.water		Overland flow hydrologic simulation using path sampling method (SIMWE).
r.slope.aspect		Generates raster maps of slope, aspect, curvatures and partial derivatives from an elevation raster map.
r.solute.transport		Numerical calculation program for transient, confined and unconfined solute transport in two dimensions
r.spread		Simulates elliptically anisotropic spread.
r.spreadpath		Recursively traces the least cost path backwards to cells from which the cumulative cost was determined.
r.statistics		Calculates category or object oriented statistics.
r.stats		Generates area statistics for raster map.
r.stats.quantile		Compute category quantiles using two passes.
r.stats.zonal		Calculates category or object oriented statistics (accumulator-based statistics).
r.stream.extract		Performs stream network extraction.
r.sun		Solar irradiance and irradiation model.
r.sunhours		Calculates solar elevation, solar azimuth, and sun hours.
r.sunmask		Calculates cast shadow areas from sun position and elevation raster map.
r.support		Allows creation and/or modification of raster map layer support files.
r.support.stats		Update raster map statistics
r.surf.area		Prints estimation of surface area for raster map.
r.surf.contour		Generates surface raster map from rasterized contours.
r.surf.fractal		Creates a fractal surface of a given fractal dimension.
r.surf.gauss		Generates a raster map using gaussian random number generator.
r.surf.idw		Provides surface interpolation from raster point data by Inverse Distance Squared Weighting.
r.surf.random		Produces a raster surface map of uniform random deviates with defined range.
r.terraflow		Performs flow computation for massive grids.
r.texture		Generate images with textural features from a raster map.
r.thin		Thins non-null cells that denote linear features in a raster map layer.
r.tile		Splits a raster map into tiles.
r.tileset		Produces tilings of the source projection for use in the destination region and projection.
r.timestamp		Modifies a timestamp for a raster map.
r.to.rast3		Converts 2D raster map slices to one 3D raster volume map.
r.to.rast3elev		Creates a 3D volume map based on 2D elevation and value raster maps.
r.to.vect		Converts a raster map into a vector map.
r.topidx		Creates a topographic index (wetness index) raster map from an elevation raster map.
r.topmodel		Simulates TOPMODEL which is a physically based hydrologic model.
r.transect		Outputs raster map layer values lying along user defined transect line(s).
r.univar		Calculates univariate statistics from the non-null cells of a raster map.
r.unpack		Imports a GRASS GIS specific raster archive file (packed with r.pack) as a raster map
r.uslek		Computes USLE Soil Erodibility Factor (K).
r.usler		Computes USLE R factor, Rainfall erosivity index.
r.viewshed		Computes the viewshed of a point on an elevation raster map.
r.volume		Calculates the volume of data "clumps".
r.walk		Creates a raster map showing the anisotropic cumulative cost of moving between different geographic locations on an input raster map whose cell category values represent cost.
r.water.outlet		Creates watershed basins from a drainage direction map.
r.watershed		Calculates hydrological parameters and RUSLE factors.
r.what.color		Queries colors for a raster map layer.
r.what		Queries raster maps on their category values and category labels.

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