Mapping and charting pertains to the topographic and geographic feature mapping of land surfaces, and the charting of coastlines and the topography of the seabed, including obstacles, shoals, and other hazards to navigation.
Space-based SAR, configured for interferometric measurements, provides a unique capability to acquire high accuracy (DTED-3 level) topographic data in a rapid, cost-effective fashion. The all-weather capability of SAR permits the acquisition of topographic measurements in cloud-covered regions and areas of denied access. SAR-derived topographic data (Figure 10-1) can augment existing topographic mapping data to yield DTED-3 level maps on a global basis.
Within the Department of Interior, the Bureau of Indian Affairs can utilize topographic and boundary maps of reservation areas, while the Bureau of Land Management has need for image-derived maps of selected regions of the U.S. The U.S. Geological Survey has broad requirements for topographic and geologic feature maps of the U.S. and selected foreign regions, particularly cloud-covered equatorial regions. The Defense Mapping Agency (DMA) has extensive need for worldwide image-derived digital terrain elevation data and hydrographic charts to support production of MC&G data for a wide range of military applications, including navigation, targeting, mission planning and rehearsal, modeling and simulations, tactical operations, and intelligence gathering. Here, too, the area of interest for SAR-derived data are the traditionally cloud covered areas within +/-15 degrees of the equator, as well as foreign regions of denied access. The Army Corps of Engineers, at the Topographic Engineering Center share many of the DMA requirements for mapping (terrain contours, classification, and feature extraction) with need for the use of interferometric SAR (IFSAR) techniques to conduct rapid mapping for a range of military applications, including targeting, support to combat operations, and mission planning, and the creation of synthetic environments to aid in training, concept development, mission rehearsals, and performance evaluations. The Drug Enforcement Administration (DEA) requires accurate topographic/terrain maps to aid in raid planning (Figure 10-2) and to support other operations, especially in cloud-covered regions such as Peru. Because these operations are most often conducted in foreign areas where access is either denied or otherwise to be avoided, space-based SAR data collection provides a unique capability for mapping purposes. The U.S. Air Force intelligence community requires IFSAR-derived image data to generate terrain battle maps and scene battle maps for use in the next generation weapons guidance systems. The IFSAR-derived maps, developed in both peacetime and during crisis periods, will provide a map-matching guidance capability to augment data from a Doppler radar altimeter and processed using advanced navigation algorithms, to provide a highly accurate weapons delivery capability. The Navy and Marine Corps have both mapping and charting requirements which support operations in the littoral battle space, including the planning and execution of amphibious landings (Figure 10-3), mine sweeping operations (Figure 10-4), and the insertion/recovery of special warfare teams (Figure 10-5). Maps of the coastal shoreline are required to define the shape and dimensions of the beach, exits, resupply points, landmarks, and obstructions. For the hinterland, topographic maps are needed to identify lines of communication, landmarks, and trafficability conditions (Figure 10-6).
NOAA requires data for charts to identify hazards to navigation, including shoaling conditions, reefs, and obstructions in the U.S near-shore regions, while the USCG has an active interest in the correct positioning of navigation hazards in ocean areas.