The 'last modified' date of the file at NGDC from which the current version of these data was obtained is 06 Feb 2004.
For those that prefer a CD-ROM to downloading data, the CD-ROM is available from NOAA NGDC.
The following text is from the "ETOPO5.DOC" documentation file which accompanied the data at the NGDC website noted above:
Information about the ETOPO5 5-minute gridded elevation data Sources for ETOPO5: ETOPO5 was generated from a digital data base of land and sea- floor elevations on a 5-minute latitude/longitude grid. The resolution of the gridded data varies from true 5-minute for the ocean floors, the U.S.A., Europe, Japan,and Australia to 1 degree in data-deficient parts of Asia, South America, northern Canada, and Africa. Data sources are as follows: Ocean Areas: U.S. Naval Oceanographic Ofice; U.S.A., W. Europe, Japan/Korea: U.S. Defense Mapping Agency; Australia: Bureau of Mineral Resources, Australia; New Zealand: Department of Industrial and Scientific Research, New Zealand; balance of world land masses: U.S. Navy Fleet Numerical Oceanographic Center. Data Formats for ETOPO5: The data file is formatted as 16-bit BINARY INTEGERS in two byte orders: ETOPO5.DOS is in IBM-PC/DEC-VAX "swapped," lo-byte-first order. The file ETOPO5.DAT is in "normal," or hi-byte-first order, as used by Macintosh, Sun, and some other workstations. In both files, there are 2160x4320 data values, one for each five minutes of latitude and longitude, for a total of 9,331,200 points or 18,662,400 bytes. Data values are in whole meters, representing the elevation of the CENTER of each cell. The files "ETOPO5.FMT;1" and ETOPO5.HDR;1" are placed in the ETOPO5 directory for convenient use of the "FREEFORM" and "GEOVU2" utilities being developed at NGDC. (These programs were not available for inclusion on the CD -- watch for an announcement of their release.) Data Order in the Files: The file may be thought of as having a logical record size of 8640 bytes. The data start at the North Pole (90 deg N, 0 deg 0' E) and are arranged in bands of 360 degrees x 12 points/degree = 4320 values (8640 bytes) ranging eastward from 0 deg 0' East longitude to 359 deg 55' East longitude (since it represents the North Pole, all possible longitudes still refer to a single point, thus the first band has 4320 identical values of -4290 m). The 8641st starts the latitude band for 89 deg 55' N, and so on. There is NO record for the South Pole (elevation 2810 m.) USING THE PC DOS ACCESS PROGRAMS FOR ETOPO5 DATA: (Macintosh users will find their own software in the Mac part of this CD-ROM) There are three programs in this directory for accessing the ETOPO5 data on a PC-compatible computer (Macintosh users will find their specific software in the "Macintosh Files:Public Software:NGDC Software" directory.). The PC programs are: 1) SELTOP1.EXE 2) SELTOP5.EXE 3) SELTOP5B.EXE Each program copies a data selection from the ETOPO5 data base to a user-specified file. The programs are run by entering set ETOPO5=SELTOPx /r 8640 where "x" is "1", "5", or "5B", and "path to ETOPO5.DOS" is the pathname to access the file "ETOPO5.DOS" from the CD-ROM, or from a copy on hard disk, e.g., "F:\TOPO\ETOPO5\ETOPO5.DOS". The command-line arguments "/r 8640" are necessary to set up a buffer for file access. As their names suggest, the three programs select data as follows: SELTOP1 copies to ASCII (text) data by 1-degree squares, SELTOP5 copies to ASCII data by 5-degree squares, and SELTOP5B copies to 16-bit binary data by 5-degree squares. Each program prompts you for the name of a file to recieve the copied data (the file name must not already exist), followed by the latitude and longitude in whole degrees of the southwest corner of the data area. The program then asks for the number of 1- or 5- degree squares north and east of the origin to be copied -- an area 30 degrees wide (W-E) and 20 degrees high (S-N) would consist of 4 (5-deg) blocks northward and 6 (5-deg) blocks eastward of the origin (or 20x30 1-degree blocks). The ASCII output files contain this type of header: "Data format: depths/elevations in whole Meters (+ = above sea level). Lat and lon are given for SouthWest corner of 1-degree square area covered by a 13x13 matrix of 5-minute grid values starting at the NorthWest corner of the square and then given Eastward along increasing longitude for 13 values, then stepping 5 minutes South for the next row (last row, first entry = SW corner point of degree square). " followed by the data. The binary files have no header.
