TerrainBase Global Land Elevation and Ocean Depth

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TerrainBase Africa Land Elevation and Ocean Depth (0-35 S, 5-60 E) (554 400 bytes Res: 5 arc minutes)

Description

The providers, NGDC, describe TerrainBase as follows:
TerrainBase is an ongoing project conducted by the National Geophysical Data Center and World Data Centers-A for Solid Earth Geophysics and for Marine Geology and Geophysics (NGDC/WDC-A) to develop a research-quality collection of digital terrain models (DTMs). The CD-ROM provided in this first release of TerrainBase contains the largest collection of digital terrain models -- ranging from regional grids at 30-minute resolution to global grids at 5- and 10-minutes -- currently available in the public domain. A total of twenty-six regional and worldwide terrain models and one newly-developed global model are included in this release. All of the models compiled on the CD-ROM are in a gridded format, meaning that the data represent a matrix of height values separated by a fixed grid interval. Numerous national and international collections, along with access software and extensive documentation, have been compiled into this easy-to-use product. The cost is $81. Please refer to product 1090-A27.

The sources of DTMs for this Global dataset

              Digital Terrain Models Available from NOAA/NGDC
                                January 1994

Coverage                Grid spacing    Topo/bathy      Developer/contributor
---------------------   -------------   -------------   ---------------------
Global land             10-minute       Topography      NCAR and FNOC
Global oceans           5-minute        Bathymetry      Washington University
North America           5-minute        Both            U.S. DMA
Europe                  5-minute        Both            U.S. DMA
Conterminous USA        30-second       Topography      NOAA/NGDC
Italy                   30-second       Both            Servizio Geol Naznl
Africa                  5-minute        Topography      Australian Natl Univ
Greenland               5x10-minute     Topography      Kort-og Matrikelstyr.
Australia               5-minute        Topography      Australian Natl Univ
Brazil Cerrados region  2-minute        Topography      Cntr Int Agr Tropical
Andes Mtns & Peru/Chile 3-minute        Both            Cornell University
     trench
Austria                 1.5x2.5-minute  Topography      Tech Univ Graz
Japan, N. and S. Korea  5-minute        Both            U.S. DMA
Netherlands             3x5-minute      Topography      Tech Univ Delft
Alaskan Arctic coast    30-second       Bathymetry      NOAA/NGDC
Bering Strait coast     30-second       Bathymetry      NOAA/NGDC
Alaska Pacific coast    30-second       Bathymetry      NOAA/NGDC
U.S. Atlantic coast     30-second       Bathymetry      NOAA/NGDC
Great Lakes             30-second       Bathymetry      NOAA/NGDC
U.S. Gulf Mexico coast  30-second       Bathymetry      NOAA/NGDC
U.S. Pacific coast      30-second       Bathymetry      NOAA/NGDC
Hawaiian Islands coast  30-second       Bathymetry      NOAA/NGDC
Puerto Rico coast       30-second       Bathymetry      NOAA/NGDC
Central NW Terr, Canada 5-minute        Both            NOAA/NGDC
Madagascar              30-second       Topography      USGS, EROS Data Center
Haiti, Dom, Republic,   30-second       Topography      USGS, EROS Data Center
and Puerto Rico

Comments concerning comparison of ETOPO5 and TerrainBase from Paula Dunbar (

pdunbar@ngdc.noaa.gov), NGDC.

In response to your e-mail, I have copied a section from the TerrainBase documentation discussing ETOPO5 and TerrainBase.

Comparison of TerrainBase with ETOPO5

ETOPO5 evolved from a 5-minute global terrain model that was initially developed in 1985 at Washington University. The model was produced as a mosaic of five source models--most of which are also included in this release of TerrainBase. Since its inception, ETOPO5 has been a very important terrain data resource for a broad array of users. Despite its popularity, it contains a large number of errors and artifacts that effectively limits the applicability of these data for certain uses. This release of TerrainBase attempts to address many of these problems.

The most significant improvement of TerrainBase in comparison to ETOPO5 is the amount and quality of source data that were used for global model development. TerrainBase has fifteen sources of data compared to five that went into producing ETOPO5. In addition, TerrainBase includes on the CD-ROM all of the source data that went into producing the global model as separate files in their original resolution, whereas ETOPO5 consists of only one global file sampled at 5 arc-minutes. Documentation has been redesigned and extended.

The TerrainBase 5-minute global model uses most of the same data that went in to developing ETOPO5; however, TerrainBase includes ten additional sources of data which provide a substantial improvement in overall quality. Most of the significant improvements in the data include the parts of the model that cover the continents of North America, South America, Europe, Africa, Greenland, and Australia. No improvements were possible for Asia, Antarctica and the oceans at the time of this release.

Although the TerrainBase 5-minute global model contains many significant artifacts (as described in Chapter 5), it provides substantial improvements in quality, structure and documentation over its predecessors.

MEMO
FROM: Steven Worley, Data Support Section
SUB: NCAR ASCII version of TerrainBase earth surface elevation
The binary data the NGDC CD-ROM was converted to ASCII and place in the same format as the earlier ETOPO5 dataset. This easy to use and portable data set has the following characteristics:

all elevations are given in meters, positive above sealevel and negative below
the grid resolution is 5 minutes x 5 minutes (long., lat.)
the data are organized in full 360 degree latitude circles beginning at 90N and stepping southward to 89 55.0S; the circle at 90N has constant value and the circle at 90S is not given, but a value of 2810 meters may be assumed
along each circle (latitude line) there are 360*12 = 4320 values
there are 180*12 = 2160 latitude lines
each logical (tape) record is 120 eight bit bytes long
one logical record contains 20 grid point values, format 20I6
216 logical records (4320 grid points) represent one latitude line of data, e.g. the first 216 logical records are used to reconstruct the elevation at 90N (all constant), the next 216 logical records apply to the elevations at 89 55.0N, and so on.
the first value on a lat. line is matched to 0E longitude, and the last value is 359 55.0E (or equivalently 0 5.0W) longitude. This last point was changed in the imatge show in this CD. In orther to homogenize all data in the CD the rows begin in -180E and end in 179 55.0E. The original data are not changed

Original source

/DSS/D/DS759.2 TERRAINBASE GLOBAL 5-MINUTE OCEAN DEPTH AND LAND ELEVATION

ftp://ncardata.ucar.edu/datasets/ds759.2
SUBJECT TO CHANGE WITHOUT NOTICE
Steve Worley
Fri Dec 1 16:39:44 MST 1995

worley@ncar.ucar.edu
(303)-497-1248

Prepared and maintained by the Data Support Section, Scientific Computing Division, National Center for Atmospheric Research. NCAR is operated by the University Corporation for Atmospheric Research and is sponsored by the National Science Foundation. Please credit when publishing research which utilized data from this archive. The original source of the data should also be acknowledged.

Direct inquiries to the person shown above, to the person[s] whose last name[s] appears on the 'specialist:' line below, or to Roy Jenne, the manager of the Data Support Section. A file of staff phone numbers and E-mail addresses may be found under the home directory in the file named staff.

First time users of our archive, or this data set, should contact the specialist[s] before attempting to access the data. We can provide users with access routines, format documentation [mentioned on the 'format refs:' line in the listing below], and advice.

Experienced users of this data set should from time to time make a new listing of this file, as we update our tapes and documentation without notice.

DATA SET:       759.2
TITLE:          TERRAINBASE GLOBAL 5-MINUTE OCEAN DEPTH AND LAND ELEVATION
SUMMARY:        GLOBAL DIGITAL ELEVATION DATA COMPILED BY NGDC.  THIS SUPER-
SUMMARY:        CEDES THE ETOPO5 DATA SET.
SUMMARY:
VOLUME:         56MB
DAN SECTIONS:
TN REFERENCES:
FORMAT REFS:

FOLDERS -
INV     INFO    PROG    SUBR    PROJ    SP.PROJ MOVIE   MICRO   MISC    REQ
I-NNN   D-NNN   P-NNN   S-NNN   PR-NNN  SPR-NNN J-NNN   M-NNN   MS-NNN  Q-NNN

TYPES:          TOPO OCEAN GRIDDED
GRIDS:          LATLON 5-MIN
LEVELS:         SFC
VARIABLES:      ELEV DEPTH
PERIODS:
TIMES:
STATISTICS:

SOURCES:        NOAA NGDC \PAULA DUNBAR
SPECIALIST:     WORLEY
PUBLICATIONS:

 -
 -              ASCII UNIX FILES, ALL RECORDS ARE LRECL=120
 Y28256         GLOBAL ASCII FILE - 56MBYTES            466560 LRECS