National Oceanic and Atmospheric Administration (NOAA), National Environmental Satellite, Data, and Information Service(NESDIS)
The U. S. Navy's Fleet Numerical Oceanography Center (FNOC) in Monterey, California, created a digital terrain model in the late 1970s, by estimat- ing maximum, minimum, and modal (most common) elevations for each 10-arc- minute grid cell superimposed on available topographic maps, generally at a scale of 1:1million. Where elevation contours were missing on available maps, the elevations were guessed at by FNOC personnel.
In addition to the three estimates for elevation, FNOC also developed estimates for the number of "ridge" lines per 10-minute grid cell, the direction of trend of these ridge lines, primary and secondary characteris- tics of terrain, and percentage of water cover. The data base is described in Cuming and Hawkins (1981), and presented in NGDC (1992).
The data were originally developed for internal use, NOT for archive and international distribution/reference. There is sketchy or nonexistent (or, at least, currently unavailable) documentation on the philosophy and me- chanics of development of each data set in this collection. Each data set is also characterized by artifacts that affect the ability of the data to be digitally analyzed. Yet each data set is an important beginning at describing features of the land surface. The data should thus be consid- ered a valuable (and pioneering) discussion on characterizing the land surface.
Incidentally, the version of FNOC used at NGDC is a copy received from the National Center for Atmospheric Research. This version contained artifacts that appear to result from data management problems at some stage of the process (between digitizing and final copying to NGDC), such as errors in copying disk-files. Some of these artifacts were documented by NCAR; others by NGDC (see the documentation for the FNOC data contained in NGDC, 1992). The archived version of the data obtained directly from FNOC was unreadable, apparently due to degradation of the original tape. NGDC has attempted to repair some of the artifacts in these data, though some arti- facts may remain.
Spatial analysis can help us to assess the philosophy of data development; as well as find, document, and sometimes repair artifacts in the data. Such analysis can thus make the data more understandable, and more usable for many applications. This discussion provides an overview of these subjects, in an effort to help the user to adapt and use the data appropri- ately.
We encourage users to contribute further discussion on this data set, as well as on ALL OTHER DATA SETS IN THE GLOBAL CHANGE DATA BASE. We also encourage users to contribute proposed improvements to the data.
The FNOC Percentage of Urban Development data set is characterized by values over 100% in certain locations, erroneously high values (though under 100%) at high northerly latitudes, horizontal and vertical trends of "urbanization" that do not exist where shown, unlikely blocks of relatively high and low values, and other artifacts. Some of these, such as the latter two characteristics, may be the result of individual interpretations of patterns by individual data entry personnel. The blocks of relatively high and low values, for instance, may have been created by different personal biases when interpreting analog patterns on maps to digital pat- terns in the data set. A vertical discontinuity in Afghanistan, for exam- ple, may denote a change in digitizers. Documentation of such artifacts is not currently available.
James Amano initiated this study of the FNOC Percentage of Urban Develop- ment as part of a study project in the Geography Department, University of Colorado. The study was performed in consultation with David Hastings of NGDC. After Amano's term of study was completed, Hastings continued with limited modifications of the data, and documentation of the effort.
Source materials for this process included the FNOCURB contained in the Global Ecosystems Database (NGDC, 1992), and Operational Navigation Charts (DMA, various dates). Editing was performed in GRASS (CERL, 1991) and a word processor.
1. The original FNOC data set contained 91 grid cells of digital value 127. These clearly erroneous values were renumbered to 255, and labeled a flag in the documentation to NGDC (1992). Inspection on Operational Navigation Charts (DMA, various dates) of all occurrences of these values showed that they occurred in areas that would normally be given a 0 value in the data set. Thus all occurrences of this value were reclassified to 0. This work was performed by James Amano, after discussion with David Hastings.
2. Northerly latitudes contained erroneously high values in unsettled or sparsely settled areas. Unsettled areas at northerly latitudes were win- dowed out of the whole data set, and reset to 0. A few similar values in Antarctica were similarly edited to 0. This work was performed by James Amano, after discussion with David Hastings.
3. A few unrealistically high values in South America were manually cor- rected. For example, an area north of Porto Alegre, Brazil, which would have 0 value in context of its surroundings, was manually changed to 0. This work was performed by James Amano, after discussion with David Hast- ings.
4. In the original FNOC data set, Southern Chile and Argentina are charac- terized by vertical stripes of relatively low values (usually 1 and 2). These stripes were manually removed by dumping the binary file to an ASCII grid, followed by editing of this grid and reinsertion of the edited grid back into the global data set. Some other manual editing modified the sizes and distributions of cities and villages in southern Chile, Argenti- na, and the Falkland (Malvinas) Islands. This work was performed by David Hastings.
Table 1 shows a histogram of FNOC Percentage of Urban Development (NGDC, 1992). Table 2 shows a histogram of Version 1.1 of Percentage of Urban Development, as revised by ourselves. The two histograms were produced by IDRISI (Eastman, 1992).
Such modifications hardly make the data perfect. However, several arti- facts have thus been reduced in importance, or eliminated.
Another question also arises over the philosophical question: "What consti- tutes percentage of urban development?" If one city is characterized by 5 story buildings, while another city is identical but for having 50 story buildings, what is the difference in percentage of urban development? If these are different levels of urban development, what constitutes 100% development? Can anything exceed this value? If one city has larger parks, is it more or less developed? If one city has more (widely avail- able and heavily trafficked) expressways for private cars, and another is better served by (heavily used) public transport, which is more highly developed? If two otherwise identical cities have different energy con- sumption, amounts of toxic emissions, or other cultural processes, how do these characteristics influence the percentage of urban development? Should agricultural or pastureland development, transportation corridors between urban centers, be reflected in this "percentage of urban develop- ment?"
Also, should there be only one data set that attempts to represent the percentage of urban development? Alternately, should there be several spatial data sets to characterize different aspects of urbanization and development, such as population density, energy consumption, alteration of the land surface, covering the land surface with impermeable materials (pavement, buildings, etc.), unnatural production/consumption of gasses and liquids, etc.? In the latter case, users could develop their own analyses, interpretations, and models of various aspects of urbanization or develop- ment, rather more sophisticated than can be covered by a single pre-de- fined, data set.
We feel that this topic should, some day, be addressed by the design and development of improved data on urbanization. In the meantime, this data set on Percentage of Urban Development may serve as a catalyst for further discussion (and cautious application) on this overall topic.
The pioneering FNOC 10-minute gridded global data base contains an initial attempt to represent the "Percentage of Urban Development." We have made some modest changes, in an attempt to repair some of the predominant arti- facts in the original version of the data.
These changes may make the data more usable in certain applications. However, they do not make the data a consistent, highly analytical, repre- sentation of urbanization, development, or any related topic. A thorough philosophical discussion, design and development of several data sets as discussed just above, may be necessary before such data are available.
CERL, 1991. Geographic Resources Analysis Support System (GRASS) Version 4.0. Geographic information system software and documentation. U. S. Army Corps of Engineers, Construction Engineering Research Laboratory, Cham- paign, Illinois, USA.
Cuming, Michael J., and Barbara A. Hawkins, 1981. TERDAT: The FNOC system for terrain data extraction and processing. Technical report MII Project M-254 (Second Edition). Prepared for Fleet Numerical Oceanography Center (Monterey, California). Published by Meteorology International Inc.
DMA, various dates. Operational Navigation Charts (global coverage at 1:1,000,000 scale, revised and published periodically). Defense Mapping Agency Aerospace Center, St. Louis, Missouri, USA. (Distributed by NOAA National Ocean Service, Office of Charting and Geodetic Services, Rock- ville, Maryland, USA.
Eastman, J. Ronald, 1992. IDRISI, Version 4.0. Geographic information system software and documentation. Graduate School of Geography, Clark University, Worcester, Massachusetts, USA.
NGDC, 1992. Global Change Data Base, Volume 1: Global Ecosystems Data. Digital Data on CD-ROM, With Documentation. NGDC #1016-A27-001. NOAA National Geophysical Data Center, Boulder, Colorado, USA.
*PERCENTAGE OF URBAN DEVELOPMENT_help
Global Ecosystems Database Disc B (Beta Version): Chapter 5
Hastings and Amano Improved FNOC Urban Development
Percentage Urban Development
DATA-SET DESCRIPTION
Data-Set Name: Improved FNOC Urban Development
Principal Investigator: David A. Hastings & James Amano
National Oceanic and Atmospheric Administration
National Geophysical Data Center
Scientific Reference:
Cuming, Michael J. and Barbara A. Hawkins, 1981. "TERDAT: The FNOC
System for Terrain Data Extraction and Processing." Technical
report MII Project M-254 (Second Edition). Prepared for Fleet
Numerical Oceanography Center (Monterey, CA). Published by
Meteorology International Incorporated.
SOURCE
Source Data Citation:
Fleet Numeric Oceanographic Center. 1985. 10-minute Global
Elevation, Terrain, and Surface Characteristics (re-processed
by NCAR and NGDC). Digital Raster Data on a 10-minute
Geographic (latitude/longitude)1080x2160 grid. Boulder, CO:
NOAA National Geophysical Data Center. 28 MB in 9 files
on 9-track tape.
Contributor:
David A. Hastings
National Oceanic and Atmospheric Administration
National Geophysical Data Center
325 Broadway, Boulder, Colorado 80303, USA
Distributor:
NOAA National Geophysical Data Center
325 Broadway, Boulder, Colorado 80303, USA
Vintage:
1993
Lineage:
(1)Digitizing from maps (elevation, terrain, and surface
characteristics):
Leo Clarke
US Navy Fleet Numerical Oceanographic Center
(2)Reprocessed with corrections to elevation values (elevation,
terrain, and surface characteristics):
Dennis Joseph
National Center for Atmospheric Research
(3)Error flags, corrections, and re-structuring (1985) (elevation,
terrain, and surface characteristics):
John J. Kineman
NOAA National Geophysical Data Center
(4)NOAA-EPA Global Ecosystems Database Project (1992) (elevation,
terrain, and surface characteristics):
NOAA National Geophysical Data Center
(5)Editing of (only) the Percentage of Urban Development data layer
for improved consistency and accuracy.
David A. Hastings and James Amano
NOAA National Geophysical Data Center
ORIGINAL DESIGN
Variables:
Percentage Urban Development
Origin:
Digitized from ONC charts and other maps as available
Geographic Reference:
Geographic (latitude/longitude)
Geographic Coverage:
Global:
Maximum Latitude: +90 degrees (N)
Minimum Latitude: -90 degrees (S)
Maximum Longitude: +180 degrees (E)
Minimum Longitude: -180 degrees(W)
Geographic Sampling:
10-minute grid characteristic percentage values
Time Period:
Modern composite circa 1970's
Temporal Sampling:
Static modern composite
INTEGRATED DATA-SET
Data-Set Citation:
NGDC. 1993. Hastings and Amano Global Improved FNOC Percentage
Urban Development. Digital Raster Data on a 10-minute Geographic
(latitude/longitude) grid. In: Global Ecosystems Database Version
1.0: Disc B, Boulder CO: NOAA National Geophysical Data Center. One
single-attribute spatial layer on CD-ROM, 2 MB in two files.
Analyst:
David A. Hastings
James Amano
Projection:
Geographic (latitude/longitude)
Spatial Representation:
10-minute grid characteristic values
Temporal Representation:
Static modern composite
Data Representation:
Eight-bit unsigned integers representing percentage of urban
development
Layers and Attributes:
One single-attribute spatial layer
Compressed Data Volume:
Approximately 43 KB
ADDITIONAL REFERENCES
see Technical Report, below
DATA FILE DESCRIPTION
DATA ELEMENT: Percentage Urban Development
STRUCTURE:
Raster Data Files: 10-minute GED 1080x2160 grid (see User's Guide)
SERIES: NONE
SPATIAL META-DATA: HAURB.DOC
file title : Hastings and Amano Improved Urban Cover (%) (ver. 1.1)
data type : byte
file type : binary
columns : 2160
rows : 1080
ref. system : lat/long
ref. units : deg
unit dist. : 1.0000000
min. X : -180.0000000
max. X : 180.0000000
min. Y : -90.0000000
max. Y : 90.0000000
pos'n error : unknown
resolution : 0.1666667
min. value : 0
max. value : 98
value units : percent
value error : unknown
flag value : none
flag def'n : none
legend cats : 0
lineage : improved at NGDC
ATTRIBUTE META-DATA: NONE
TECHNICAL REPORT
David A. Hastings
National Oceanic and Atmospheric Administration
National Geophysical Data Center
325 Broadway, Boulder, Colorado 80303, USA
James Amano
Department of Geography
University of Colorado
Boulder, Colorado 80309, USA
Background
The U. S. Navy's Fleet Numerical Oceanography Center (FNOC) in
Monterey, California, created a digital terrain model in the late
1970s, by estimating maximum, minimum, and modal (most common)
elevations for each 10-arc-minute grid cell superimposed on
available topographic maps, generally at a scale of 1:1million.
Where elevation contours were missing on available maps, the
elevations were guessed at by FNOC personnel.
In addition to the three estimates for elevation, FNOC also
developed estimates for the number of "ridge" lines per 10-minute
grid cell, the direction of trend of these ridge lines, primary and
secondary characteristics of terrain, and percentage of water
cover. The data base is described in Cuming and Hawkins (1981), and
presented in NGDC (1992).
The data were originally developed for internal use, NOT for
archive and international distribution/reference. There is sketchy
or nonexistent (or, at least, currently unavailable) documentation
on the philosophy and mechanics of develop- ment of each data set
in this collection. Each data set is also characterized by
artifacts that affect the ability of the data to be digitally
analyzed. Yet each data set is an important beginning at describing
features of the land surface. The data should thus be considered a
valuable (and pioneering) discus- sion on characterizing the land
surface.
Incidentally, the version of FNOC used at NGDC is a copy received
from the National Center for Atmospheric Research. This version
contained artifacts that appear to result from data management
problems at some stage of the process (between digitizing and final
copying to NGDC), such as errors in copying disk-files.
Some of these artifacts were documented by NCAR; others by NGDC
(see the documentation for the FNOC data contained in NGDC, 1992).
The archived version of the data obtained directly from FNOC was
unreadable, apparently due to degrada- tion of the original tape.
NGDC has attempted to repair some of the artifacts in these data,
though some artifacts may remain.
Spatial analysis can help us to assess the philosophy of data
development; as well as find, document, and sometimes repair
artifacts in the data. Such analysis can thus make the data more
understandable, and more usable for many applications. This
discussion provides an overview of these subjects, in an effort to
help the user to adapt and use the data appropriately.
We encourage users to contribute further discussion on this data
set, as well as on ALL OTHER DATA SETS IN THE GLOBAL CHANGE DATA
BASE. We also encourage users to contribute proposed improvements
to the data.
Artifacts in the Data
The FNOC Percentage of Urban Development data set is characterized
by values over 100% in certain locations, erroneously high values
(though under 100%) at high northerly latitudes, horizontal and
vertical trends of "urbanization" that do not exist where shown,
unlikely blocks of relatively high and low values, and other
artifacts. Some of these, such as the latter two characteristics,
may be the result of individual interpretations of patterns by
individual data entry personnel.
The blocks of relatively high and low values, for instance, may
have been created by different personal biases when interpreting
analog patterns on maps to digital patterns in the data set. A
vertical discontinuity in Afghanistan, for example, may denote a
change in digitizers. Documentation of such artifacts is not
currently available.
James Amano initiated this study of the FNOC Percentage of Urban
Development as part of a study project in the Geography Department,
University of Colorado. The study was performed in consultation
with David Hastings of NGDC. After Amano's term of study was
completed, Hastings continued with limited modifications of the
data, and documentation of the effort.
Source materials for this process included the FNOCURB contained in
the Global Ecosystems Database (NGDC, 1992), and Operational
Navigation Charts (DMA, various dates). Editing was performed in
GRASS (CERL, 1991) and a word processor.
The work consisted of the following steps:
1. The original FNOC data set contained 91 grid cells of digital
value 127. These clearly erroneous values were renumbered to 255,
and labeled a flag in the documentation to NGDC (1992). Inspection
on Operational Navigation Charts (DMA, various dates) of all
occurrences of these values showed that they occurred in areas that
would normally be given a 0 value in the data set. Thus all
occurrences of this value were reclassified to 0. This work was
performed by James Amano, after discussion with David Hastings.
2. Northerly latitudes contained erroneously high values in
unsettled or sparsely settled areas. Unsettled areas at northerly
latitudes were windowed out of the whole data set, and reset to 0.
A few similar values in Antarctica weresimilarly edited to 0. This
work was performed by James Amano, after discussion with David
Hastings.
3. A few unrealistically high values in South America were manually
corrected. For example, an area north of Porto Alegre, Brazil,
which would have 0 value in context of its surroundings, was
manually changed to 0. This work was performed by James Amano,
after discussion with David Hastings.
4. In the original FNOC data set, Southern Chile and Argentina are
characterized by vertical stripes of relatively low values (usually
1 and 2). These stripes were manually removed by dumping the binary
file to an ASCII grid, followed by editing of this grid and reinsertion
of the edited grid back into the global data set. Some other manual
editing modified the sizes and distributions of cities and villages in
southern Chile, Argentina, and the Falkland (Malvinas) Islands. This
work was performed by David Hastings.
Table 1 shows a histogram of FNOC Percentage of Urban Development
(NGDC, 1992). Table 2 shows a histogram of Version 1.1 of
Percentage of Urban Development, as revised by ourselves. The two
histograms were produced by IDRISI (Eastman, 1992).
Such modifications hardly make the data perfect. However, several
artifacts have thus been reduced in importance, or eliminated.
How Should We Represent "Percentage of Urban Development?"
Another question also arises over the philosophical question: "What
constitutes percentage of urban development?" If one city is
characterized by 5 story buildings, while another city is identical
but for having 50 story buildings, what is the difference in
percentage of urban development? If these are different levels of
urban development, what constitutes 100% development? Can anything
exceed this value? If one city has larger parks, is it more or less
developed? If one city has more (widely available and heavily
trafficked) expressways for private cars, and another is better
served by (heavily used) public transport, which is more highly
developed? If two otherwise identical cities have different energy
consumption, amounts of toxic emissions, or other cultural
processes, how do these characteristics influence the percentage of
urban development?
Should agricultural or pasture land development, transportation
corridors between urban centers, be reflected in this "percentage
of urban development?"
Also, should there be only one data set that attempts to represent
the percent age of urban development? Alternately, should there be
several spatial data sets to characterize different aspects of
urbanization and development, such as population density, energy
consumption, alteration of the land surface, covering the land
surface with impermeable materials (pavement, buildings, etc.),
unnatural production/consumption of gasses and liquids, etc.? In
the latter case, users could develop their own analyses,
interpretations, and models of various aspects of urbanization or
development, rather more sophisticated than can be covered by a
single pre-defined, data set.
We feel that this topic should, some day, be addressed by the
design and development of improved data on urbanization. In the
meantime, this data set on Percentage of Urban development may
serve as a catalyst for further discussion (and cautious
application) on this overall topic.
Conclusion
The pioneering FNOC 10-minute gridded global data base contains an
initial attempt to represent the "Percentage of Urban Development."
We have made some modest changes, in an attempt to repair some of
the predominant artifacts in the original version of the data.
These changes may make the data more usable in certain
applications. However, they do not make the data a consistent,
highly analytical, representation of urbanization, development, or
any related topic. A thorough philosophical discussion, design and
development of several data sets as discussed just above, may be
necessary before such data are available.
References
CERL, 1991. Geographic Resources Analysis Support System (GRASS)
Version 4.0. Geographic information system software and
documentation. U. S. Army Corps of Engineers, Construction
Engineering Research Laboratory, Champaign, Illinois, USA.
Cuming, Michael J., and Barbara A. Hawkins, 1981. TERDAT: The FNOC
system for terrain data extraction and processing. Technical report
MII Project M-254 (Second Edition). Prepared for Fleet Numerical
Oceanography Center (Monterey, California). Published by
Meteorology International Inc.
DMA, various dates. Operational Navigation Charts (global coverage at
1:1,000,000 scale, revised and published periodically). Defense
Mapping Agency Aerospace Center, St. Louis, Missouri, USA. (Distributed
by NOAA National Ocean Service, Office of Charting and Geodetic
Services, Rockville, Maryland, USA.
Eastman, J. Ronald, 1992. IDRISI, Version 4.0. Geographic information
system software and documentation. Graduate School of Geography,
Clark University, Worcester, Massachusetts, USA.
NGDC, 1992. Global Change Data Base, Volume 1: Global Ecosystems
Data. Digital Data on CD-ROM, With Documentation. NGDC #1016-A27-
001. NOAA National Geophysical Data Center, Boulder, Colorado, USA.
=============================================
Data editing performed January-May 1993. Documentation written
11 May 1993.
*PERCENTAGE OF URBAN DEVELOPMENT
ANCILLARY ENVIRONMENTAL DATA
Hastings and Amano Improved Urban Cover (%) (ver. 1.1)
#\data\ncillary\haurb.img