GRASS

GRASS GIS 6.1.cvs 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

vector commands:
v.buffer Create a buffer around features of given type (areas must contain centroid).
v.build.all v.build.all
v.build Creates topology for GRASS vector data.
v.build.polylines Build polylines from lines.
v.category Attach, delete or report vector categories to map geometry.
v.clean Toolset to clean vector topology
v.convert.all v.convert.all
v.convert Imports older versions of GRASS vectors.
v.db.addcol v.db.addcol
v.db.addtable v.db.addtable
v.db.connect Prints/sets DB connection for a vector map
v.db.droptable v.db.droptable
v.db.reconnect.all v.db.reconnect.all
v.db.select Print vector attributes
v.db.update v.db.update
v.delaunay Create a Delaunay triangulation from an input vector of points or centroids.
v.digit
v.distance Find the nearest element in vector 'to' for elements in vector 'from'. Various information about this relation may be uploaded to the attribute table of input vector 'from' or printed to stdout.
v.drape Convert 2D vector to 3D vector by sampling of elevation raster. Default sampling by nearest neighbor
v.external Create a new vector as a read-only link to OGR layer. Available drivers:
v.extract Selects vector objects from an existing vector map and creates a new map containing only the selected objects. If 'list', 'file' and 'where' options are not specified, all features of given type and layer are extracted, categories are not changed in that case.
v.extrude Extrudes flat vector object to 3D with defined height
v.hull Uses a GRASS vector points map to produce a convex hull vector map
v.in.ascii Convert GRASS ascii file or points file to binary vector.
v.in.db Create new vector (points) from database table containing coordinates.
v.in.dxf Converts files in DXF format to GRASS vector file format.
v.in.e00 v.in.e00
v.in.garmin v.in.garmin
v.in.gns v.in.gns
v.in.gpsbabel v.in.gpsbabel
v.in.mapgen v.in.mapgen
v.in.ogr Convert OGR vectors to GRASS. Available drivers:
v.in.region Create a new vector from current region.
v.in.sites.all v.in.sites.all
v.in.sites Converts a GRASS site_lists file into a vector file.
v.info Outputs basic information about a user-specified vector map layer.
v.kcv Randomly partition points into test/train sets.
v.kernel Generates a raster density map from vector points data using a moving 2D isotropic Gaussian kernel or optionally generates a vector density map on vector network with a 1D kernel
v.label Create paint labels for GRASS vector file and attached attributes.
v.lrs.create Create Liner reference system
v.lrs.label Create stationing from imput lines, and linear reference system
v.lrs.segment Create points/segments from imput lines, linear reference system and positions read from stdin in format:
v.lrs.where Find line id and real km+offset for given points in vector map using linear reference system
v.mkgrid Creates a (binary) GRASS vector map of a user-defined grid.
v.neighbors Makes each cell value a function of the attribute values assigned to the vector points or centroids around it, and stores new cell values in an output raster map layer.
v.net.alloc Allocate subnets for nearest centres (direction from centre). Centre node must be opened (costs >= 0). Costs of centre node are used in calculation
v.net Network maintenance.
v.net.iso Split net to bands between cost isolines (direction from centre). Centre node must be opened (costs >= 0). Costs of centre node are used in calculation
v.net.path Find shortest path on vector network. Reads start/end pointsfrom standard input in 2 possible formats:
v.net.salesman Create a cycle connecting given nodes (Traveling salesman problem). Note that TSP is NP-hard, heuristic algorithm is used by this module and created cycle may be sub optimal.
v.net.steiner Create Steiner tree for the network and given terminals. Note that 'Minimum Steiner Tree' problem is NP-hard and heuristic algorithm is used in this module so the the result may be sub optimal.
v.normal tests for normality for points.
v.out.ascii Convert a GRASS binary vector map to a GRASS ASCII vector map
v.out.dxf Exports GRASS vector files to DXF file format.
v.out.ogr Convert to one of the supported OGR vector formats.
v.out.pov Convert to POV-Ray format, GRASS x,y,z -> POV-Ray x,z,y
v.out.vtk Convert a GRASS binary vector map to VTK ASCII output
v.overlay Overlay 2 vector maps.
v.parallel Create parallel line to input lines.
v.patch Creates a new binary vector map layer by combining other binary vector map layers.
v.perturb Random location perturbations of GRASS vector points
v.proj Allows projection conversion of vector files.
v.qcount indices for quadrat counts of sites lists
v.random Randomly generate a 2D/3D GRASS vector points map.
v.rast.stats v.rast.stats
v.reclass Changes vector category values for an existing vector map according to results of SQL queries or a value in attribute table column.
v.report v.report
v.sample Sample a raster file at site locations
v.segment Create points/segments from input lines, and positions read from stdin in format:
v.select Select features from ainput by features from binput
v.split Split lines to shorter segments.
v.surf.idw Surface interpolation from vector point data by Inverse Distance Squared Weighting.
v.surf.rst Spatial approximation and topographic analysis from given point or isoline data in vector format to floating point raster format using regularized spline with tension.
v.to.db Load values from vector to database. In uploaded/printed category values '-1' is used for 'no category' and 'null'/'-' if category cannot be found or multiple categories were found.
v.to.points Create points along input lines.
v.to.rast Converts a binary GRASS vector map layer into a GRASS raster map layer.
v.to.rast3 Converts a binary GRASS vector map (only points) layer into a 3D GRASS raster map layer.
v.transform Transforms an vector map layer from one coordinate system into another coordinate system.
v.type Change the type of geometry elements.
v.univar Calculates univariate statistics for attribute. Variance and standard deviation is calculated only for points if specified
v.univar.sh v.univar.sh
v.vol.rst Interpolates point data to a G3D grid volume using regularized spline with tension (RST) algorithm
v.voronoi Create a Voronoi triangulation from an input vector of points or centroids.
v.what Allows the user to interactively query a vector map layer at user-selected locations within the current geographic region
v.what.rast Uploads raster values at positions of vector points to the table
v.what.vect v.what.vect


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