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 `project` from rgdal.

### 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, https://www.nceas.ucsb.edu/scicomp/recipes/projections and the help for `project` in the related package rgdal. 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 from https://www.gpsbabel.org/. 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). Or ";C:/Program Files/gpsbabel" on 32-bit systems.

### See Also

`make.systematic`, `readGPS`

### Examples

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

    ## Not run:

    datadir <- system.file("extdata", package = "secr")
    possumarea <- rgdal::readOGR(dsn = datadir, layer = "possumarea")

    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)

[Package secr version 3.2.1 Index]