tbase - Read 5-minute global terrain elevations from TerrainBase

Syntax

[Z,refvec] = tbase(scalefactor) [Z,refvec] = tbase(scalefactor,latlim,lonlim)

Description

[Z,refvec] = tbase(scalefactor) reads the data for the entire world, reducing the resolution of the data by the specified scale factor. The result is returned as a regular data grid and an associated three-element referencing vector.

[Z,refvec] = tbase(scalefactor,latlim,lonlim) reads the data for the part of the world within the latitude and longitude limits. The limits must be two-element vectors in units of degrees.

Background

TerrainBase is a global model of terrain and bathymetry on a regular 5-minute grid (approximately 10 km resolution). It is a compilation of the best available public domain data from almost 20 different sources, including the DCW-DEM and ETOPO5. The model is currently under development and will be updated as new data sources become available. The data set was created by the National Geophysical Data Center and World Data Center-A for Solid Earth Geophysics in Boulder, Colorado.

Remarks

Elevations and depths are given in meters above or below mean sea level.

The tbase.bin file is available on CD-ROM from

NOAA/NGDC
Mail Code E/GC3
325 Broadway
Boulder, CO  80303
USA
Tel: (303) 497-6338
Fax: (303) 497-6513

The data and documentation are available over the Internet via http and anonymous ftp.

Note For details on locating map data for download over the Internet, see the following documentation at the MathWorks Web site: http://www.mathworks.com/support/tech-notes/2100/2101.html.

No byte-swapping or line-ending conversion is required.

Examples

Read every 10th point in the data set:

[Z,refvec] = tbase(10);
whos

  Name              Size         Bytes  Class

  Z               216x432       746496  double array
  refvec            1x3             24  double array

limitm(Z,refvec)

ans =
   -90    90     0   360

Read data for Korea and Japan at the full resolution:

scalefactor = 1; latlim = [30 45]; lonlim = [115 145];
[Z,refvec] = tbase(scalefactor,latlim,lonlim);
whos datagrid

  Name       Size         Bytes  Class

  Z        180x360       518400  double array