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)

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

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