USGS CMG A-1-02-MD Metadata

The LIDAR-derived data were collected by the Maryland Department of
Natural Resources in support of shore erosion studies along the shorelines of
the Chesapeake Bay. It also supports the Federal Emergency Management Agency's
specifications for mapping floodplains. These efforts required detailed
elevation data and models, such as those available from LIDAR sensing. The
data have also been made available to aid in other projects that require
detailed surface, vegetation and/or structure elevations.

Light Detection and Ranging (LIDAR) is a method of locating objects
on the ground using aerial-borne equipment. It is similar to RADAR or SONAR in
that the two-way travel time of an energy beam reflected off an object is
precisely measured, but this technology uses laser light instead of radio or
sound waves. This technology has proven very useful in remote sensing of the
earth. It can be used for determining elevations of both the earth's surface
and items (natural and man-made) on the surface. Analysis of LIDAR data is used
in detailed modeling of the earth's surface for drainage and floodplain studies,
determining how a new structure will affect views from various locations,
shoreline erosion studies, and other reasons. The Bare Earth Mass Points are
point elevations that represent the "bare earth." Features that are above the
ground - such as buildings, bridges, tree tops, etc. - have been eliminated.