GRS80 Geodetic Reference System of 1980

GSD ground sample distance

HEC Hydrologic Engineering Center (USACE)

HMS Hydrologic Modeling System

IFSAR interferometric synthetic aperture radar

IMU inertial measurement unit

InSAR interferometric synthetic aperture radar (also IFSAR)

JPL Jet Propulsion Laboratory (NASA)

lidar light detection and ranging

LOMA Letter of Map Amendment

LOMR Letter of Map Revision

MAPPS Management Association for Private Photogrammetric Surveyors

MHIP Multi-year Flood Hazard Identification Plan

MPIA multiple-pulse-in-the-air

NAD27 North American Datum of 1927

NAD83 North American Datum of 1983

NAIP National Agriculture Imagery Program (USDA)

NAPP National Aerial Photography Program

NASA National Aeronautics and Space Administration

NAVD88 North American Vertical Datum of 1988

NDEP National Digital Elevation Program

NDOP National Digital Orthophoto Program

NED National Elevation Dataset

NFIP National Flood Insurance Program

NGA National Geospatial-Intelligence Agency

NGS National Geodetic Survey

NGVD29 National Geodetic Vertical Datum of 1929

NMAS National Map Accuracy Standards

NOAA National Oceanic and Atmospheric Administration

NSDI National Spatial Data Infrastructure

NSGIC National States Geographic Information Council

NSSDA National Standard for Spatial Data Accuracy