An ecological assessment of the United States mid-Atlantic region using rank frequency distributions based on watershed quintiles


When working with raw data for multiple environmental indicators, it can be difficult to assess quality or ‘health’ because of the large number of indicators and inconsistencies among the indicators. By grouping the raw data into rankings, the data become more manageable and more comprehensible. We do not, however, want to lose information as a result of the groupings. It is possible to assess the quality of grouping options graphically by seeing if the resulting assessments of ‘health’ are concordant with the raw data. This can be done through the use of CDF-index values, cumulative distribution function plots, parallel coordinates plots, and scatterplots. A major purpose of this paper is to present approaches and the graphics for comparison and prioritization based on quintiles used, in this case, for ecological assessment of a large region.



Cumulative Distribution Function


Environmental Protection Agency


  1. Jones, B. K., K.H. Ritters, J. D. Wickham, R. D. Tankersley Jr., R. V. O’Neill, D. J. Chaloud, E. R. Smith, A. C. Neale. 1997. An Ecological Assessment of the United States Mid-Atlantic Region: A Landscape Atlas. EPA 600-R-97-130, United States Environmental Protection Agency, Office of Research and Development, Washington, D.C.

    Google Scholar 

  2. Wegman, E. J. 1990. “Hyperdimensional data analysis using parallel coordinates,” Journal of the American Statistical Association 85, 664–675.

    Article  Google Scholar 

  3. Environmental Protection Agency, (1999). Data on “Additional Information about Watershed Indicators,” downloaded from

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Correspondence to G. P. Patil.

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Patil, G.P., Taillie, C. & Vraney, R. An ecological assessment of the United States mid-Atlantic region using rank frequency distributions based on watershed quintiles. COMMUNITY ECOLOGY 3, 1–8 (2002).

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  • Comparison and prioritization
  • Ecological assessment
  • Multiple watershed indicators
  • Nine-tiles
  • Parallel coordinates plots
  • Quintiles
  • Rank distribution function plots
  • Rank frequency distribution
  • Septiles
  • Triangle composition plots