writeGPS {secr}

R Documentation

Upload to GPS

Description

Upload a set of point locations as waypoints to a GPS unit connected by USB or via a serial port. Intended primarily for detector locations in a traps object. Uses the GPSBabel package which must have been installed. Coordinates are first inverse-projected to latitude and longitude using function st_transform from sf.

Usage

writeGPS(xy, o = "garmin", F = "usb:", proj = "+proj=nzmg")

Arguments

xy	2-column matrix or dataframe of x-y coordinates
o	character output format (see GPSBabel documentation)
F	character for destination (see Details)
proj	character string describing projection

Details

This function is derived in part from readGPS in maptools.

For users of Garmin GPS units, useful values of o are "garmin" for direct upload via USB or serial ports, and "gdb" for a file in Mapsource database format.

F may be "usb:" or "com4:" etc. for upload via USB or serial ports, or the name of a file to create.

The proj argument may be complex. For further information see the Examples and the vignette secr-spatialdata.pdf. If proj is an empty string then coordinates are assumed already to be latitudes (column 1) and longitudes (column 2).

Waypoint names are derived from the rownames of xy.

Value

No value is returned. The effect is to upload waypoints to an attached GPS or file.

Note

GPSBabel is available free online. Remember to add it to the path. On Windows this means following something like Settings > Control panel > System > Advanced settings > Environment variables > (select Path) Edit and adding ";C:/Program Files (x86)/gpsbabel" to the end (without the quotes).

See Also

make.systematic

Examples

## Example using shapefile "possumarea.shp" in
## "extdata" folder. As 'cluster' is not specified,
## the grid comprises single multi-catch detectors.

## Not run: 

## test for availability of GPSBabel

if (nzchar(Sys.which("gpsbabel"))) {

library(sf)
shpfilename <- system.file("extdata/possumarea.shp", package = "secr")
possumarea <- st_read(shpfilename)

possumgrid <- make.systematic(spacing = 100, region = possumarea, 
    plt = TRUE)

## May upload directly to GPS...
# writeGPS(possumgrid, proj = "+proj=nzmg")

## ...or save as Mapsource file
writeGPS(possumgrid, o = "gdb", F = "tempgrid.gdb",
    proj = "+proj=nzmg")

## If `region' had been specified in another projection we
## would need to specify this as in Proj.4. Here is a
## hypothetical example for New Zealand Transverse Mercator
## with datum NZGD2000 (EPSG:2193)

NZTM <- paste("+proj=tmerc +lat_0=0 +lon_0=173 +k=0.9996",
    "+x_0=1600000 +y_0=10000000 +ellps=GRS80",
    " +towgs84=0,0,0,0,0,0,0 +units=m +no_defs")

# writeGPS(possumgridNZTM, o = "gdb", F = "tempNZTM.txt", 
#    proj = NZTM)

## Or to upload coordinates from UTM Zone 18 in eastern
## Maryland, USA...

# writeGPS(MarylandUTMgrid, proj = 
#    "+proj=utm +zone=18 +ellps=WGS84")

}


## End(Not run)

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