Get topographic data

Retrieves topographic data from ETOPO1 Global Relief Model (see references).

Usage

GetTopography(
  lon.west,
  lon.east,
  lat.north,
  lat.south,
  resolution = 3.5,
  cache = TRUE,
  file.dir = tempdir(),
  verbose = interactive()
)

Arguments

lon.west, lon.east, lat.north, lat.south

latitudes and longitudes of the bounding box in degrees

resolution

numeric vector indicating the desired resolution (in degrees) in the lon and lat directions (maximum resolution is 1 minute)

cache

logical indicating if the results should be saved on disk

file.dir

optional directory where to save and/or retrieve data

verbose

logical indicating whether to print progress

Value

A data table with height (in meters) for each longitude and latitude.

Details

Very large requests can take long and can be denied by the NOAA server. If the function fails, try with a smaller bounding box or coarser resolution.

Longitude coordinates must be between 0 and 360.

References

Source: Amante, C. and B.W. Eakins, 2009. ETOPO1 1 Arc-Minute Global Relief Model: Procedures, Data Sources and Analysis. NOAA Technical Memorandum NESDIS NGDC-24. National Geophysical Data Center, NOAA. doi:10.7289/V5C8276M

Examples

if (FALSE) { # \dontrun{
topo <- GetTopography(280, 330, 0, -60, resolution = 0.5)
library(ggplot2)
ggplot(topo, aes(lon, lat)) +
    geom_raster(aes(fill = h)) +
    geom_contour(aes(z = h), breaks = 0, color = "black", size = 0.3) +
    scale_fill_gradient2(low = "steelblue", high = "goldenrod2", mid = "olivedrab") +
    coord_quickmap()
} # }