Operational Navigation Charts Source/Platform Document
Operational Navigation Charts (ONCs) are a series of worldwide small-scale (1:1,000,000) aeronautical charts that provide topographic information for air navigation. They are designed for medium-altitude, high-speed visual and radar navigation and are also used for operational planning and intelligence briefings. They were used in 1992 as the basis of a Digital Chart of the World, a comprehensive vector base map of the world sponsored by the U.S. Defense Mapping Agency (now the U.S. National Imagery and Mapping Agency). The global information available from the ONCs enables scientists to study the state of the global biosphere and to perform environmental monitoring, planning and crisis management, data intercomparison, and model testing.
ONCs were integrated with United Nations Educational Scientific and Cultural Organization (UNESCO) maps of vegetation and with Food and Agriculture Organization (FAO) soil maps to to produce a high-resolution, global database for evaluating natural wetlands and estimating their methane emissions.
Table of Contents:
- Operational Navigation Charts, ONCs
- ONCs are aeronautical charts produced produced by the United States, Australia, Canada, and the United Kingdom for use as en route medium-altitude (2,000 to 25,000 feet) navigational aids. They show elevation, topography, cultural features, and hydrography. ONCs were integrated with two other independent digital sources--vegetation maps following the UNESCO system (Matthews, 1983) and FAO maps of soil properties (Zobler, 1986)--to produce a high-resolution global database for evaluating natural wetlands and their methane emissions. The ONCs provided fractional inundation data from 1-degree cells of a global map survey and were the most up-to-date and consistent of the three sources. Aerial photography is the fundamental mapping tool, and the large scale of the series provides the potential for representing more realistic detail than do most of the smaller-scale sources used in compiling the other two databases.
- The objectives of the ONCs are to provide global topographic information for air navigation, operational planning, and intelligence briefings and to provide a source of global information systems data.
- ONCs have a scale of 1:1,000,000 (1 inch equals approximately 16 miles) and measure 42 inches x 57 1/4 inches, covering 8 degrees of latitude.
- The ONCs together have a coverage of all the world's land data at a scale of at 1:1,000,000 and show elevation (500-m contours), cultural features, and hydrography. They are maintained for air navigation, and the currency of the charts ranges from the mid-1960s to the early 1990s.
Every ONC includes brief annotations, such as the years in which the original base map was prepared and updated, as well as warnings about unreliable relief information, but there is no overall evaluation of the reliability of the maps, especially for features other than those of critical importance to pilots. In short, while the ONC map series are considered to be quite reliable, uncertainties in the database derived from these maps can emanate from (1) the possible lack of surveys in inaccessible regions; (2) the inability to determine, particularly in tropical regions that undergo seasonal expansion and contraction of inundated areas, whether inundation on the maps reflects maximum, minimum, or intermediate wetland extent; and (3) the imprecision of the inundation overprint and the overlay grid method for deriving fractional inundation for cells (Matthews and Fung, 1987).
- Information about sensors/instruments is not applicable to the ONCs.
- The ONCs used aerial photography, but more detailed information on the development of the ONCs is not readily available.
Matthews, E., 1983. Global vegetation and land use: New high-resolution data bases for climate studies. Journal of Climate and Applied Meteorology 22:474-87.
Matthews, E., and I. Fung, 1987. Methane emission from natural wetlands: Global distribution, area, and environmental characteristics of the sources. Global Biogeochemical Cycles 1(1):61-86.
Zobler, L., 1986. A world soil file for global climate modeling. NASA Technical Memorandum 87802. Goddard
Institute for Space Studies. New York.
On-line information is available at the following World Wide Web sites:
GISS Matthews Wetlands Database and Methane Emission Data Set (ORNL-DAAC)
Natural Wetlands (Matthews and Fung)
Disclaimer: Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
- A glossary is available at
- Food and Agriculture Organization (United Nations)
- National Aeronautics and Space Administration
- Operational Navigation Charts
- Oak Ridge National Laboratory
- United Nations Educational, Scientific, and Cultural Organization
- Uniform Resource Locator
- A list of acronyms is available at http://cdiac.esd.ornl.gov/cdiac/pns/acronyms.html.
- July 21, 1998
- July 28, 1998
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Revision Date: Monday, 20-Dec-2010 14:16:23 EST