DESCRIPTION
r.random.cells generates a random sets of cells that are at
least distance apart. The cells are numbered from 1 to the
numbers of cells generated. Random cells will not be generated in
areas masked off.
Detailed parameter description
- output
- Random cells. Each random cell has a unique non-zero cell value
ranging from 1 to the number of cells generated. The heuristic for
this algorithm is to randomly pick cells until there are no cells
outside of the chosen cell's buffer of radius distance.
- distance
- Determines the minimum distance the centers of the random cells
will be apart.
- seed
- Specifies the random seed that
r.random.cells will use to generate the cells. If the random seed
is not given, r.random.cells will get a seed from the process ID
number.
NOTES
The original purpose for this program was to generate independent
random samples of cells in a study area. The distance value is
the amount of spatial autocorrelation for the map being studied.
REFERENCES
Random Field Software for GRASS by Chuck Ehlschlaeger
As part of my dissertation, I put together several programs that help
GRASS (4.1 and beyond) develop uncertainty models of spatial data. I hope
you find it useful and dependable. The following papers might clarify their
use:
- Ehlschlaeger, C.R., Shortridge, A.M., Goodchild, M.F., 1997.
Visualizing spatial data uncertainty using animation.
Computers & Geosciences 23, 387-395. doi:10.1016/S0098-3004(97)00005-8
- Modeling
Uncertainty in Elevation Data for Geographical Analysis, by
Charles R. Ehlschlaeger, and Ashton M. Shortridge. Proceedings of the
7th International Symposium on Spatial Data Handling, Delft,
Netherlands, August 1996.
- Dealing
with Uncertainty in Categorical Coverage Maps: Defining, Visualizing,
and Managing Data Errors, by Charles Ehlschlaeger and Michael
Goodchild. Proceedings, Workshop on Geographic Information Systems at
the Conference on Information and Knowledge Management, Gaithersburg
MD, 1994.
- Uncertainty
in Spatial Data: Defining, Visualizing, and Managing Data
Errors, by Charles Ehlschlaeger and Michael
Goodchild. Proceedings, GIS/LIS'94, pp. 246-253, Phoenix AZ,
1994.
SEE ALSO
r.random.surface,
r.random
AUTHOR
Charles Ehlschlaeger; National Center for Geographic Information and
Analysis, University of California, Santa Barbara.
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