stamp.direction: Perform polygon directional analysis

Description Usage Arguments Details Value References See Also

View source: R/stamp.direction.r

Description

stamp.direction facilitates polygon directional analysis using a variety of methods.

Usage

1
stamp.direction(stmp, dir.mode = "CentroidAngle", ndir = 4, group = FALSE)

Arguments

stmp

a SpatialPolygonsDataFrame object generated from the stamp function.

dir.mode

a character item identifying which directional relations method is to be used. See Details for information on each individual method.

ndir

(optional) parameter identifying the number of directions to be computed. See inidividual method Details for appropriate usage.

group

(optional) a logical value identifying whether direction should be computed on groups or individual event polygons (only used with CentroidAngle method).

Details

The stamp.direction function can be used to facilitate directional analysis on output stamp.obj objects from function stamp. Currently, four directional analysis methods are available:

Value

Appends the input stamp object with appropriate columns for the directional analysis chosen, if dir.mode is:

"CentroidAngle"

A single column with centroid angle results, in degrees (North = 0 degrees). If group=TRUE then values are identical for all event polygons in the group.

"ConeModel"

ndir new columns with the area of the STAMP event in each direction, named appropriately (e.g., as DIR45, where 45 refers to the mid-point of that directional cone).

"MBRModel"

9 new columns with the area of the STAMP event in each direction, named appropriately as "SW","S","SE","W","SAME","E","NW","N","NE".

"ModConeModel"

ndir new columns with the area of the STAMP event in each direction, named appropriately as, for example, "N","E","S","W" with ndir=4.

Note: STAMP events that are singular (i.e., only 1 polygon in the group) will have NA's from directional analysis.

References

Robertson, C., Nelson, T., Boots, B., and Wulder, M. (2007) STAMP: Spatial-temporal analysis of moving polygons. Journal of Geographical Systems, 9:207-227.

Peuquet, D., Zhang, C.X. (1987) An algorithm to determine the directional relationship between arbitrarily-shaped polygons in the plane. Pattern Recognition, 20:65-74.

Skiadopoulos, S. Giannoukos, C., Sarkas, N., Vassiliadis, P., Sellis, T., and Koubarakis, M. (2005) Computing and managing directional relations. IEEE Transactions on Knowledge and Data Engineering, 17:1610-1623.

See Also

stamp, stamp.distance, stamp.shape


stampr documentation built on April 19, 2018, 1:04 a.m.