GRASS GIS 6.2.4cvs 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.centroids Adds missing centroids to closed boundaries

v.clean Toolset to clean vector topology

v.convert.all v.convert.all

v.convert Imports older versions of GRASS vector maps.

v.db.addcol Adds one or more columns to the attribute table connected to a given vector map

v.db.addtable Creates and adds a new attribute table to a given layer of an existing vector map.

v.db.connect Prints/sets DB connection for a vector map to attribute table

v.db.droptable removes existing attribute table of a vector map

v.db.reconnect.all Reconnect vectors to a new database

v.db.select Print vector attributes

v.db.update Allows to assign a new value to a column in the attribute table connected to a given map

v.delaunay Create a Delaunay triangulation from an input vector map containing points or centroids.

v.digit Interactive editing and digitization of vector maps.

v.dissolve Dissolve boundaries between adjacent areas sharing a common category number or attribute

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 Import of E00 file into a vector map.

v.in.garmin Upload Waypoints, Routes, and Tracks from a Garmin GPS receiver into a vector map.

v.in.gns Imports US-NGA GEOnet Names Server (GNS) country files into a GRASS vector points map

v.in.gpsbabel Import waypoints, routes, and tracks from a GPS receiver or GPS download file into a vector map.

v.in.mapgen Import Mapgen or Matlab vector maps into GRASS.

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.lidar.correction Correction of the v.lidar.growing output. It is the last of the three algorithms for LIDAR filtering

v.lidar.edgedetection Detect the object's edges from a LIDAR data set.

v.lidar.growing Building contour determination and Region Growing algorithm for determining the building inside

v.lrs.create Create Linear Reference System

v.lrs.label Create stationing from input lines, and linear reference system

v.lrs.segment Create points/segments from input lines, linear reference system and positions read from stdin or a file

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.

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.outlier Removes outliers from vector point data

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 Calculates univariate statistics from a GRASS raster map based on vector polygons and uploads statistics to new attribute columns

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 Reports geometry statistics for vectors.

v.sample Sample a raster file at site locations

v.segment Create points/segments from input lines and and positions.

v.select Select features from ainput by features from binput

v.split Split lines to shorter segments.

v.surf.bspline Bicubic or bilinear spline interpolation with Tykhonov regularization

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 Calculates univariate statistics on selected table column for a GRASS vector map

v.vol.rst Interpolates point data to a G3D grid volume using regularized spline with tension (RST) algorithm

v.voronoi Create a Voronoi diagram from an input vector map containing points or centroids.

v.what Queries a vector map layer at given locations

v.what.rast Uploads raster values at positions of vector points to the table

v.what.vect Uploads vector values at positions of vector points to the table

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.centroids	Adds missing centroids to closed boundaries
v.clean	Toolset to clean vector topology
v.convert.all	v.convert.all
v.convert	Imports older versions of GRASS vector maps.
v.db.addcol	Adds one or more columns to the attribute table connected to a given vector map
v.db.addtable	Creates and adds a new attribute table to a given layer of an existing vector map.
v.db.connect	Prints/sets DB connection for a vector map to attribute table
v.db.droptable	removes existing attribute table of a vector map
v.db.reconnect.all	Reconnect vectors to a new database
v.db.select	Print vector attributes
v.db.update	Allows to assign a new value to a column in the attribute table connected to a given map
v.delaunay	Create a Delaunay triangulation from an input vector map containing points or centroids.
v.digit	Interactive editing and digitization of vector maps.
v.dissolve	Dissolve boundaries between adjacent areas sharing a common category number or attribute
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	Import of E00 file into a vector map.
v.in.garmin	Upload Waypoints, Routes, and Tracks from a Garmin GPS receiver into a vector map.
v.in.gns	Imports US-NGA GEOnet Names Server (GNS) country files into a GRASS vector points map
v.in.gpsbabel	Import waypoints, routes, and tracks from a GPS receiver or GPS download file into a vector map.
v.in.mapgen	Import Mapgen or Matlab vector maps into GRASS.
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.lidar.correction	Correction of the v.lidar.growing output. It is the last of the three algorithms for LIDAR filtering
v.lidar.edgedetection	Detect the object's edges from a LIDAR data set.
v.lidar.growing	Building contour determination and Region Growing algorithm for determining the building inside
v.lrs.create	Create Linear Reference System
v.lrs.label	Create stationing from input lines, and linear reference system
v.lrs.segment	Create points/segments from input lines, linear reference system and positions read from stdin or a file
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.
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.outlier	Removes outliers from vector point data
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	Calculates univariate statistics from a GRASS raster map based on vector polygons and uploads statistics to new attribute columns
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	Reports geometry statistics for vectors.
v.sample	Sample a raster file at site locations
v.segment	Create points/segments from input lines and and positions.
v.select	Select features from ainput by features from binput
v.split	Split lines to shorter segments.
v.surf.bspline	Bicubic or bilinear spline interpolation with Tykhonov regularization
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	Calculates univariate statistics on selected table column for a GRASS vector map
v.vol.rst	Interpolates point data to a G3D grid volume using regularized spline with tension (RST) algorithm
v.voronoi	Create a Voronoi diagram from an input vector map containing points or centroids.
v.what	Queries a vector map layer at given locations
v.what.rast	Uploads raster values at positions of vector points to the table
v.what.vect	Uploads vector values at positions of vector points to the table