Projection

Functions to manipulate the coordinate reference system (CRS) of ctmm objects

# S4 method for telemetry
projection(x,asText=TRUE)

# S4 method for ctmm
projection(x,asText=TRUE)

# S4 method for UD
projection(x,asText=TRUE)

# S4 method for list
projection(x,asText=TRUE)

# S4 method for NULL
projection(x,asText=TRUE)

# S4 method for telemetry
projection(x) <- value

# S4 method for list
projection(x) <- value

# S3 method for telemetry
median(x,na.rm=FALSE,...)

compass(loc=NULL,cex=3,...)

Arguments

x

A telemetry, ctmm, or UD object.

asText

If TRUE, the projection is returned as text. Otherwise a CRS object is returned.

value

Projection to apply. Can also be a data.frame of longitude-latitude foci.

na.rm

Not used.

...

Arguments passed to Gmedian or text.

loc

Optional two-dimensional coordinates (in meters) at which to draw a north-facing compass needle.

cex

Relative size of compass.

Details

projection(x) returns the projection information from ctmm object x, while projection(x) <- value applies the projection value to object x. median(x) returns the ellipsoidal geometric median of a telemetry object. compass(c(x,y)) plots a north-pointing compass needle at the coordinates \((x,y)\).

Author

C. H. Fleming

Note

Plotting UTF-8 chracters in a PDF, like the compass needle, requires specifying a compatible font family. For example:

library(ctmm)
data(buffalo)
cairo_pdf(file="buffalo.pdf",family="DejaVu Sans")
plot(buffalo[[1]])
compass()
dev.off()

See also

as.telemetry.

Examples

# Load package and data
library(ctmm)
data(buffalo)

# Apply a 1-point projection that preserves North==up
projection(buffalo) <- median(buffalo)
plot(buffalo)
#> DOP values missing. Assuming DOP=1.
#> DOP values missing. Assuming DOP=1.
#> DOP values missing. Assuming DOP=1.
#> DOP values missing. Assuming DOP=1.
#> DOP values missing. Assuming DOP=1.
#> DOP values missing. Assuming DOP=1.
compass()


# Apply a 2-point projection safer for elongated disributions
projection(buffalo) <- median(buffalo,k=2)
# This is the default projection for ctmm
plot(buffalo)
#> DOP values missing. Assuming DOP=1.
#> DOP values missing. Assuming DOP=1.
#> DOP values missing. Assuming DOP=1.
#> DOP values missing. Assuming DOP=1.
#> DOP values missing. Assuming DOP=1.
#> DOP values missing. Assuming DOP=1.
compass()