jitterDupCoords {geoR}

Jitters (duplicated) coordinates.

Description

Jitters 2D coordinates uniformily on a region around (duplicated) points.

Usage

jitter2d(coords, max, min = 0.2 * max, fix.one = TRUE,
         which.fix = c("random", "first", "last")) 

jitterDupCoords(x, ...)

## Default S3 method:
jitterDupCoords(x, ...)

## S3 method for class 'geodata'
jitterDupCoords(x, ...)

Arguments

x, coords

a matrix or data frame with 2D coordinates or geodata object.

max

numeric scalar defining maximum jittering distance.

min

numeric scalar defining minimum jittering distance.

fix.one

logical. Whether or not one of the coordinates should not be jittered.

which.fix

single element vector of integer or character, defining which coordinate won't be jittered. Only used if fix.one=TRUE.

...

arguments passed to jitter2d.

Value

jitter2d returns an object of the same type fo the input with jittered values

jitterDupCoords returns an object of the same type fo the input with jittered coordinate values only at the duplicated locations

Author(s)

Paulo Justiniano Ribeiro Jr. [e-mail],
Peter J. Diggle [e-mail].

See Also

dup.coords, duplicated.geodata for functions identifying duplicated locations.

Examples

## simulating data
dt <- grf(30, cov.p=c(1, .3)) 
dt$coords <- round(dt$coords, dig=2)
## "forcing" some duplicated locations
dt$coords[4,] <- dt$coords[14,] <- dt$coords[24,] <- dt$coords[2,]
dt$coords[17,] <- dt$coords[23,] <- dt$coords[8,]

## jittering a matrix of duplicated coordinates
dt$coords[c(2,4,14,24),]
jitter2d(dt$coords[c(2,4,14,24),], max=0.01)

## jittering only the duplicated locations and comparing with original
cbind(dt$coords, jitterDupCoords(dt$coords, max=0.01))

## creating a now geodata object jittering the duplicated locations of the original one:
dup.coords(dt)
dt1 <- jitterDupCoords(dt, max=0.01)
dup.coords(dt1)