LAKEMAP: A 2‐D AND 3‐D MAPPING SYSTEM FOR VISUALIZING WATER QUALITY DATA IN LAKES1

Abstract

ABSTRACT: The visualization of water quality data in lakes was achieved by integrating the U.S. Environmental Protection Agency's (EPA) STORET water quality database, lake shoreline polygons from EPA's Reach File (version 3), and the UNIMAP 2‐D and 3‐D interactive mapping and modeling software. Based on lake name (and state abbreviation), a lake shoreline polygon can be accessed from the Reach File. The coordinates of the polygon are portrayed by the U.S. Geological Survey (USGS) 1:100,000 scale Digital Line Graph (DLG) hydrography layer. This polygon is passed, in turn, to the STORET water quality file. Monitoring stations located within the polygon boundary are extracted along with the complete sampling survey. Specific parameters, such as total phosphorus, pH, ammonia, and optional time and depth restrictions can be selected to build a file of x, y, z1, z1…, zn data which is imported to UNIMAP. Up to four parameters, including depth, can be selected at a time. Within UNIMAP, the data is gridded and then displayed as a 2‐D color contour map, 3‐D perspective contour map, or 2‐D projected time or depth slices. This system operates on the EPA ES9000 mainframe computer located in Research Triangle Park (RIP), North Carolina. LAKEMAP is the culmination of an effort to bridge the gap between the vast array of environmental data collected by the EPA and the complex analytical and display software resident on the mainframe.