Vector coverages are encoded as arc-node topology, using a georelational model to associate attributes with map features. Raster coverages are stored in two-dimensional arrays with 1 to 4 bytes per cell and a cell resolution of 100 meters, although some data have a finer resolution. Supporting information provides various metadata elements. Prepayment is required on all orders. We regret that we can not give discounts or refunds.
Prices are subject to change without notice.
Government purchase orders are also accepted as payment. On foreign orders, prepayment must be in U.S. funds drawn on a U.S. bank or by an International Money Order. Shipping and handling for domestic orders are included in the cost.