A major civic service of USPS and its members is Cooperative Charting -- the contribution of correction data for nautical and aeronautical charts, reports on marine facilities, and condition of geodetic survey markers (benchmarks) to the National Oceanic and Atmospheric Administration (NOAA) and National Ocean Service (NOS), both of the U.S. Department of Commerce.
USPS contributes the largest number of chart correction reports, although NOAA and NOS also obtain data from the U.S. Navy, U.S. Coast Guard, U.S. Coast Guard Auxiliary, and Civil Air Patrol, among others.
Owners of appropriate boats can also contribute by doing channel surveys, using a depth sounder. Members without boats can participate in the program in any of four ways: by serving as crew on a member's boat, by turning in reports on marina facilities, by checking aeronautical charts, (from a car), for correctness, or by reporting on the condition of geodetic survey markers, or benchmarks. These markers are used in surveying and map making, and finding them is like a treasure hunt.