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User Guide and 
Documentation for the 
Chesapeake Bay Interpolator 
INTRODUCTION 
The Chesapeake Bay and Tidal Tributary Interpolator computes water quality 
concentrations throughout the Chesapeake Bay and/or tributary rivers from water 
quality measured at point locations. The purpose of the Interpolator is in compute 
water quality concentrations at all locations in the 2-dimensional plane (top or 
bottom depth) or throughout the 3-dimensional water volume. Results of the inter¬ 
polation can then be compared over time to compute trends or individual 
interpolations can be overlaid with other data to visualize possible cause and effect 
relationships. One example is to compare water quality with living resource (fish, 
shellfish, aquatic vegetation) distributions. Results of the Chesapeake Bay Interpo¬ 
lator have been used since 1988 to determine trends in water quality for the 
Chesapeake Bay Program (http://www.chesapeakebay.net/). 
Version 4.2 of the VOL3D software includes new code to: 1) import data from 
Microsoft ACCESS data tables; 2) draw improved graphics of tributary segments; 3) 
draw colors using categories, as before, or to draw using a color ramp of 255 colors; 
4) draw longitudinal sections which represent the centerline of the Bay or Tributary 
River segments; 5) draw images of all Tributary Rivers in addition to the Bay; and, 
6) compute composite images that represent the minimums or maximums over a 
time series. 
Another tool, DART, which must be run on the CIMS network at the Chesapeake 
Bay Program Office, creates data sets for the Interpolator for any parameter in the 
historical water quality data base. DART is a very powerful tool which can create 
many data sets in a very short time. Anyone who needs to interpolate data held by 
the Bay Program, should investigate the use of DART. 
appendix d 
User Guide and Documentation for the Chesapeake Bay Interpolator 
