Add scalebar to frames

This function adds a scalebar to frames created with frames_spatial.

Usage

add_scalebar(
  frames,
  distance = NULL,
  height = 0.015,
  position = "bottomleft",
  x = NULL,
  y = NULL,
  colour = "black",
  label_margin = 1.2,
  units = "km",
  verbose = TRUE
)

Arguments

frames: an object of class moveVis created with frames_spatial.
distance: numeric, optional. Distance displayed by the scalebar (in either km or miles defined by argument units) By default, the displayed distance is calculated automatically.
height: numeric, height of the scalebar in a range from 0 to 1 as the proportion of the overall height of the frame map. Default is 0.015.
position: character, position of the scalebar on the map. Either "bottomleft", "upperleft", "upperright", "bottomright". Ignored, if x and y are set.
x: numeric, position of the bottom left corner of the scalebar on the x axis. If not set, position is used to calculate the position of the scalebar.
y: numeric, position of the bottom left corner of the scalebar on the y axis. If not set, position is used to calculate the position of the scalebar.
colour: character, colour of the distance labels. Default is "black".
label_margin: numeric, distance of the labels to the scalebar as a proportion of the height of the scalebar (e.g. if set to 2, the labels will be positioned with a distance to the scalebar of twice the scalebar height).
units: character, either "km" for kilometers or "miles" for miles.
verbose: logical, if TRUE, messages and progress information are displayed on the console (default).

Value

A frames object of class moveVis.

Details

For adding more sophisticated map features, I recommend using ggspatial.

Author

Jakob Schwalb-Willmann

Examples

library(moveVis)
library(move2)
library(terra)

data("move_data", package = "moveVis")
r <- readRDS(example_data(file = "raster_NDVI.rds"))

# align movement
m <- align_move(move_data, res = units::set_units(4, "min"))
#> Temporal resolution of 4 [min] is used to align trajectories.

# create frames and add scaleebar
frames <- frames_spatial(m, r, r_type = "gradient", fade_raster = TRUE) %>%
  add_scalebar()
#> Processing input data...
#> Approximated animation duration: ≈ 7.52s at 25 fps using 188 frames
#> CRS (geodetic):   WGS 84
#> Assigning raster maps to frames...
frames[[100]]


# or in white at another position
frames <- frames_spatial(m, r, r_type = "gradient", fade_raster = TRUE) %>%
  add_scalebar(colour = "white", position = "bottomright")
#> Processing input data...
#> Approximated animation duration: ≈ 7.52s at 25 fps using 188 frames
#> CRS (geodetic):   WGS 84
#> Assigning raster maps to frames...
frames[[100]]


# or with another height
frames <- frames_spatial(m, r, r_type = "gradient", fade_raster = TRUE) %>%
  add_scalebar(colour = "white", position = "bottomright", height = 0.025)
#> Processing input data...
#> Approximated animation duration: ≈ 7.52s at 25 fps using 188 frames
#> CRS (geodetic):   WGS 84
#> Assigning raster maps to frames...
frames[[100]]