Read a file that contains topographic data in the ETOPO dataset, as was once provided by the NOAA website (see download.topo() for a good server for such files. (As of May, 2020, there does not seem to be a way to download these files from the NOAA website.)

read.topo(file, encoding = "latin1", debug = getOption("oceDebug"))



Name of a file containing an ETOPO-format dataset. Three types are permitted; see “Details”.




an integer specifying whether debugging information is to be printed during the processing. This is a general parameter that is used by many oce functions. Generally, setting debug=0 turns off the printing, while higher values suggest that more information be printed. If one function calls another, it usually reduces the value of debug first, so that a user can often obtain deeper debugging by specifying higher debug values.


A topo object.


The three permitted file types are as follows.

  1. An ascii type in which line 1 holds a label (which is ignored), whitespace, and then the number of columns in the matrix (i.e. the number of longitude values), line 2 is similar but for latitude, line 3 is similar but for the westernmost longitude, line 4 is similar but for southernmost latitude, line 5 is similar but for cell size, and lines after that hold the grid.

  2. A NetCDF format that was once described by NOAA as "GMT NetCDF".

  3. A NetCDF format that was once described by NOAA as "NetCDF".

Sample of Usage

topoMaritimes <- read.topo("topoMaritimes.asc")

See also


Dan Kelley