A Geographic Information System (GIS) was developed to evaluate its utility in an eradication program of common crupina. Infested areas were recorded in the GIS along with information normally found on United States Geological Survey topographic maps. Infested areas were separated into management areas according to possible treatment method and special environmental or health requirements such as proximity to streams or inhabited buildings. The location, size, and type of each management area were recorded in the database. The database was constructed to maintain treatment and efficacy data for tracking the process of eradication for each infestation. Areas were identified for detection surveying, including coordinates for navigating with a global positioning system (GPS).

Experiments were conducted to test the accuracy of a global positioning system (GPS) in measuring the area of simulated weed patches of varying size and to determine the accuracy in navigating back to particular points in a field. Circular areas of 5, 50, and 500 m2 were established and measured using point and polygon features of a GPS. The GPS estimations of the area of those patches had errors ranging from 7 to 45%, 6 to 15%, and 3 to 6%, respectively, when compared to actual measurements. As patch size increased, errors decreased. A curve describing the relationship between GPS error and patch size had an excellent fit (r 2 = 0.92). The error remained the same in all measurements across all patch sizes, but composed a smaller percentage of large patches. The GPS had submeter accuracy in navigation to the correct quadrat 73% of the time, located the correct quadrat 27% of the time, and invariably navigated to within 1.58 m of the correct quadrat. The relationship between patch size and measurement error was applied to natural infestations of hemp dogbane.