Elevation

n. The height of a geographic location above a fixed reference point, often mean sea level.

 

  • Discussion

 

Elevation, or geometric height, is used when referring to points on the earth’s surface, whereas altitude is used for points above the earth’s surface.

 

In  a geographic information system (GIS), digital elevation models (DEM) are commonly used to represent the surface (topography) of a place through a raster (grid) data set of elevations.  Spatial data layers representing elevation, slope, and aspect can be developed within a GIS using information from a DEM. This information is required for spatial fire modeling systems  such as FARSITE or FlamMap.

 

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In the past, digital elevation data were available based on a 7.5-minute topographic quadrangle extent. To create a digital representation of elevation for a large area required the user to download multiple files, merge them together, and account for data issues arising from the merging process. Currently, the U.S. Geological Survey has numerous seamless digital elevation data products available that can be accessed via the Internet (see http://edc.usgs.gov/products/elevation.html). See AMS (2000), USGS (2000), and Whiteman (2000) for further discussion.

 

 

  • Units

     

    Preferred units for elevation are m in technical reports and papers. Fire Management in the United States still uses the English units ft. See the following elevation  units conversion table for conversion factors.

     

  • See Also

  • References

    • American Meteorological Society (AMS). 2000. Glossary of Meteorology. [Online]. Available: http://amsglossary.allenpress.com/glossary.

    • United States Geological Survey (USGS). 2000. Digital Elevation Models. [Online]. Available: http://edc.usgs.gov/products/elevation/dem.html.

    • Whiteman, David C. 2000. Mountain Meteorology: Fundamentals and Applications. New York, NY: Oxford University Press, Inc. 355 pp.
       

  • Notes

    • Author 

      Charles W. McHugh, Fire Spatial Analyst

      Rocky Mountain Research Station