Spatial Grids and Their Role in Supporting Design & Analyses

Overview of Discrete Grids

• Global vs Regional
• Cell Shape (hexagons, diamonds, squares, etc.)
• Hierarchical

Background: Development of EMAP spatial grid (aka 640 km2 hexagons)

The EMAP approach for generating global grids, developed starting in 1989, used a large hexagon face of the truncated icosahedron placed on the earth to generate hexagon grids of various sizes that had the property of equal area. The grids generated by this system are limited in extent to an area of about 4500 kilometers in diameter. A large number of grids have been generated with this system. These equal area hexagons are currently used in the USGS-BRD GAP program and related applications.

Current Strategies and Applications for Aquatic Resource Monitoring

• Grid & cell construction based on triangles, diamonds and hexagons
• Area coverage for small study boundaries to global coverage
• Cell address strategies that support Hierarchical Randomization

Links for Additional Information and Programs can be found on the WED webpage maintained by Denis White, EPA/ORD/NHEERL/WED.

Bibliography also contains a limited number of references.

Check the development of the grid system by Discrete Global Grid Researchers in the Department of Computer Sciences at Southern Oregon University.