GRASS Toolbox vector data modules

GRASS Toolbox vector data modules

This Section lists all graphical dialogs in the GRASS Toolbox to work with and analyse vector data in a currently selected GRASS location and mapset. <P>
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Table 26: GRASS Toolbox: Develop vector map modules

Develop vector map modules in the GRASS Toolbox
Module name	Purpose
v.build.all	Rebuild topology of all vectors in the mapset
v.clean.break	Break lines at each intersection of vector map
v.clean.snap	Cleaning topology: snap lines to vertex in threshold
v.clean.rmdangles	Cleaning topology: remove dangles
v.clean.chdangles	Cleaning topology: change the type of boundary dangle to line
v.clean.rmbridge	Remove bridges connecting area and island or 2 islands
v.clean.chbridge	Change the type of bridges connecting area and island or 2 islands
v.clean.rmdupl	Remove duplicate lines (pay attention to categories!)
v.clean.rmdac	Remove duplicate area centroids
v.clean.bpol	Break polygons. Boundaries are broken on each point shared between 2 and more polygons where angles of segments are different
v.clean.prune	Remove vertices in threshold from lines and boundaries
v.clean.rmarea	Remove small areas (removes longest boundary with adjacent area)
v.clean.rmline	Remove all lines or boundaries of zero length
v.clean.rmsa	Remove small angles between lines at nodes
v.type.lb	Convert lines to boundaries
v.type.bl	Convert boundaries to lines
v.type.pc	Convert points to centroids
v.type.cp	Convert centroids to points
v.centroids	Add missing centroids to closed boundaries
v.build.polylines	Build polylines from lines
v.segment	Creates points/segments from input vector lines and positions
v.to.points	Create points along input lines
v.parallel	Create parallel line to input lines
v.dissolve	Dissolves boundaries between adjacent areas
v.drape	Convert 2D vector to 3D vector by sampling of elevation raster
v.transform	Performs an affine transformation on a vector map
v.proj	Allows projection conversion of vector files
v.support	Updates vector map metadata
generalize	Vector based generalization

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Table 27: GRASS Toolbox: Database connection modules

Database connection modules in the GRASS Toolbox
Module name	Purpose
v.db.connect	Connect a vector to database
v.db.sconnect	Disconnect a vector from database
v.db.what.connect	Set/Show database connection for a vector

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Table 28: GRASS Toolbox: Change vector field modules

Change vector field modules in the GRASS Toolbox
Module name	Purpose
v.category.add	Add elements to layer (ALL elements of the selected layer type!)
v.category.del	Delete category values
v.category.sum	Add a value to the current category values
v.reclass.file	Reclass category values using a rules file
v.reclass.attr	Reclass category values using a column attribute (integer positive)

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Table 29: GRASS Toolbox: Working with vector points modules

Working with vector points modules in the GRASS Toolbox
Module name	Purpose
v.in.region	Create new vector area map with current region extent
v.mkgrid.region	Create grid in current region
v.in.db	Import vector points from a database table containing coordinates
v.random	Randomly generate a 2D/3D GRASS vector point map
v.kcv	Randomly partition points into test/train sets
v.outlier	Romove outliers from vector point data
v.hull	Create a convex hull
v.delaunay.line	Delaunay triangulation (lines)
v.delaunay.area	Delaunay triangulation (areas)
v.voronoi.line	Voronoi diagram (lines)
v.voronoi.area	Voronoi diagram (areas)

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Table 30: GRASS Toolbox: Spatial vector and network analysis modules

Spatial vector and network analysis modules in the GRASS Toolbox
Module name	Purpose
v.extract.where	Select features by attributes
v.extract.list	Extract selected features
v.select.overlap	Select features overlapped by features in another map
v.buffer	Vector buffer
v.distance	Find the nearest element in vector 'to' for elements in vector 'from'.
v.net.nodes	Create nodes on network
v.net.alloc	Allocate network
v.net.iso	Cut network by cost isolines
v.net.salesman	Connect nodes by shortest route (traveling salesman)
v.net.steiner	Connect selected nodes by shortest tree (Steiner tree)
v.patch	Create a new vector map by combining other vector maps
v.overlay.or	Vector union
v.overlay.and	Vector intersection
v.overlay.not	Vector subtraction
v.overlay.xor	Vector non-intersection

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Table 31: GRASS Toolbox: Vector update by other maps modules

Vector update by other maps modules in the GRASS Toolbox
Module name	Purpose
v.rast.stats	Calculates univariate statistics from a GRASS raster map based on vector objects
v.what.vect	Uploads map for which to edit attribute table
v.what.rast	Uploads raster values at positions of vector points to the table
v.sample	Sample a raster file at site locations

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Table 32: GRASS Toolbox: Vector report and statistic modules

Vector report and statistic modules in the GRASS Toolbox
Module name	Purpose
v.to.db	Put geometry variables in database
v.report	Reports geometry statistics for vectors
v.univar	Calculates univariate statistics on selected table column for a GRASS vector map
v.normal	Tests for normality for points

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