Log In to Download Data
Need help? See our frequently asked questions or contact us.
We have taken considerable care to ensure that these topographic survey data and derived images are as accurate as possible. We believe most of these data are adequate for determination of flood hazards, for geologic mapping, for hydrologic modelling, for determination of slope angles, for modelling of radio-wave transmission, and similar uses with a level of detail appropriate to a horizontal scale of 1:12,000 (1 inch = 1,000 feet) or smaller and vertical accuracy on the order of a foot. Locally, the data are of considerably poorer quality.
Users should carefully determine the place-to-place accuracy and fitness of these data for their particular purposes. For many purposes a site- and use-specific field survey will be necessary.