v.rast.move

Move vertices by distance specified in a raster

Command linePython (grass.script)

v.rast.move input=name x_raster=name y_raster=name [nulls=string] output=name [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

v.rast.move input=name x_raster=name y_raster=name output=name

grass.script.run_command("v.rast.move", input, x_raster, y_raster, nulls="warning", output, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("v.rast.move", input="name", x_raster="name", y_raster="name", output="name")

Parameters

Command linePython (grass.script)

input=name [required]
    Name of input vector map
    Or data source for direct OGR access
x_raster=name [required]
    Name of input raster map
y_raster=name [required]
    Name of input raster map
nulls=string
    Handling of null values
    zeros;Null value will be converted to zeros;warning;A null value will cause a warning (one for each raster) and will be converted to zero;error;A null value will cause an error
    Allowed values: zeros, warning, error
    Default: warning
output=name [required]
    Name for output vector map
--overwrite
    Allow output files to overwrite existing files
--help
    Print usage summary
--verbose
    Verbose module output
--quiet
    Quiet module output
--qq
    Very quiet module output
--ui
    Force launching GUI dialog

input : str, required
    Name of input vector map
    Or data source for direct OGR access
    Used as: input, vector, name
x_raster : str, required
    Name of input raster map
    Used as: input, raster, name
y_raster : str, required
    Name of input raster map
    Used as: input, raster, name
nulls : str, optional
    Handling of null values
    zeros;Null value will be converted to zeros;warning;A null value will cause a warning (one for each raster) and will be converted to zero;error;A null value will cause an error
    Allowed values: zeros, warning, error
    Default: warning
output : str, required
    Name for output vector map
    Used as: output, vector, name
overwrite: bool, optional
    Allow output files to overwrite existing files
    Default: False
verbose: bool, optional
    Verbose module output
    Default: False
quiet: bool, optional
    Quiet module output
    Default: False
superquiet: bool, optional
    Very quiet module output
    Default: False

DESCRIPTION

v.rast.move takes values from raster maps and adds them to X and Y coordinates of features in a vector map vertex by vertex. Works on lines only, other features are ignored and not included in the result. Null values in rasters are turned into zeros by default and a warning is generated. This behavior can be modified by the nulls option to either silence the warning with explicit nulls="zeros" or the warning can be turned into an error with nulls="error". The rasters are loaded based on the computational region, so the most advantageous use of resources is to set the computational region to match the vector. To avoid issues with vector coordinates at the border of the computational region, it is best to also grow the region one cell on each side. Vector features outside of the computational region always result in an error being reported (regardless of the nulls option), but the rasters can have any extent as along as the computational region is set to match the vector.

NOTES

Unlike v.perturb which moves points randomly, v.rast.move works on vertices of lines and uses same value for all vertices at a given cell. Unlike v.transform used with raster values in attribute columns, v.rast.move operates on individual vertices in the line, not on the whole line (attributes are associated with features, not their vertices).

EXAMPLES

Shift in X direction

This example uses the North Carolina sample dataset. Set the computational region to match the vector map and use 100-meter resolution.

g.region vector=roadsmajor res=100

Generate rasters for a shift in X direction (one raster is a wave, the other is zero):

g.region vector=roadsmajor res=100
r.mapcalc expression="a = 1000 * sin(row())"
r.mapcalc expression="b = 0"

Use the rasters to move the vector:

v.rast.move input=roadsmajor output=roads_moved x_raster=a y_raster=b

Figure: Original (blue) and shifted (red) road network and the X shift values in diverging blue-white-red colors (red shift right, blue shift left, white no shift)

AUTHOR

Vaclav Petras, NCSU Center for Geospatial Analytics, GeoForAll Lab

SOURCE CODE

Available at: v.rast.move source code (history)
Latest change: Friday Feb 21 10:10:05 2025 in commit 7d78fe3