GetTopography function

Get topographic data

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

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

Returns

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.

Examples

## Not run:

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()
## End(Not run)

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. tools:::Rd_expr_doi("10.7289/V5C8276M")