to_map function

Plot location data on a map

Function to plot tracking data on a map or a satellite image.

to_map(
  sdata,
  xlim = NULL,
  ylim = NULL,
  margin = 10,
  bgmap = NULL,
  google.key = NULL,
  map.bg = "grey",
  map.col = "black",
  zoom = NULL,
  point.bg = "yellow",
  point.col = "black",
  point.symbol = 21,
  point.size = 1,
  line.col = "lightgrey",
  line.type = 1,
  line.size = 0.5,
  title = "id",
  title.size = 11,
  axes.text.size = 11,
  axes.lab.size = 11,
  multiplot = TRUE,
  nrow = 1,
  ncol = 1
)

Arguments

• sdata: A data frame containing columns with the following headers: "id", "DateTime", "lat", "lon". The function creates a map for each unique "id" (e.g. transmitter number, identifier for each animal). "DateTime" is the GMT date & time of each location in class POSIXct

  or character with the following format "2012-06-03 01:33:46". "lat" and "lon" are the latitude and longitude of each location in decimal degrees.

• xlim, ylim: Limits for x and y axes. If not specified, the values are determined as the maximum range of the input data plus an additional margin (see margin).

• margin: Set the amount of spaces added around the periphery of the plot. The value is scaled to the plot. The smaller value increases the margin.

• bgmap: A data frame of a background map data, containing the following headers: "long", "lat", "group". If not specified, the world map is used. Google Maps ("terrain", "satellite", "roadmap", "hybrid") can also be queried.

• google.key: If Google Maps are queried, a valid API key (a string) needs to be specified here. See register_google for details.

• map.bg: Background colour of the map. This argument is ignored when any Google Maps is selected.

• map.col: Outline colour of the map. This argument is ignored when any Google Maps is selected.

• zoom: Map zoom for Google Maps. Default (NULL) to estimate the zoom from each data set. For other options, see get_map for details.

• point.bg: The colour to fill in a symbol.

• point.col: The colour for the outline of a symbol.

• point.symbol: An integer or a string to specify the symbol type. See shape for details.

• point.size: An integer to specify the size of the symbol.

• line.col: The colour of the line that connects consecutive points.

• line.type: The type of the line that connects consecutive points. See linetype for details.

• line.size: An integer to specify the thickness (width) of the line that connects consecutive points.

• title: The main title for each plot. If not specified, the "id" will be used.

• title.size: An integer to specify the size of the title.

• axes.text.size: An integer to specify the size of the axes characters.

• axes.lab.size: An integer to specify the size of the axes labels.

• multiplot: Logical. If TRUE (default), multiple plots are displayed on the same page.

• nrow: An integer to specify the number of rows in the multiple plot page.

• ncol: An integer to specify the number of columns in the multiple plot page.

Returns

An arrangelist is returned when multiplot is TRUE. Otherwise a list is returned.

Examples

#### Load data sets
## Fastloc GPS data obtained from two green turtles
data(turtle)
data(turtle2)
turtles<-rbind(turtle, turtle2)

#### Filter temporal and/or spatial duplicates
turtle.dup <- dupfilter(turtles, step.time=5/60, step.dist=0.001)
 

#### ddfilter
V <- vmax(turtle.dup)
VLP <- vmaxlp(turtle.dup)
turtle.dd <- ddfilter(turtle.dup, vmax=V, vmaxlp=VLP)

#### Plot filtered data for each animal
## using the low-resolution world map
to_map(turtle.dd, point.size = 2, line.size = 0.5, axes.lab.size = 0, ncol=2, nrow=1)

## Not run:

## using the high-resolution google satellite images
to_map(turtle.dd, bgmap = "satellite", google.key = "key", ncol=2)
## End(Not run)

See Also

dupfilter, ddfilter, vmax, vmaxlp

Author(s)

Takahiro Shimada