These files contain topographic lidar data classified as ground (2) and unclassified (1) in accordance with the American Society for Photogrammetry and Remote Sensing (ASPRS) classification standards. These data were collected by the Compact Hydrographic Airborne Rapid Total Survey (CHARTS) system along the coast of Maryland. CHARTS integrates topographic and bathymetric lidar sensors, a digital camera and a hyperspectral scanner on a single remote sensing platform for use in coastal mapping and charting activities. Data coverage generally extends along the coastline from the waterline inland 500 meters (topography) and offshore 1,000 meters or to laser extinction (bathymetry). The topographic lidar sensor has a pulse repetition rate of 9 kHz at 1064 nm (near-infrared wavelength). The bathymetric lidar sensor has a pulse repetition rate of 1 kHz at 532 nm (green wavelength). Native lidar data is not generally in a format accessible to most Geographical Information Systems (GIS). Specialized in-house and commercial software packages are used to process the native lidar data into 3-dimensional positions that can be imported into GIS software for visualization and further analysis. Horizontal positions, provided in decimal degrees of latitude and longitude, are referenced to the North American Datum of 1983 (NAD83). Vertical positions are referenced to the NAD83 ellipsoid and provided in meters. The National Geodetic Survey's (NGS) GEOID03 model is used to transform the vertical positions from ellipsoid to orthometric heights referenced to the North American Vertical Datum of 1988 (NAVD88). The 3-D position data are sub-divided into a series of LAS files, each covering approximately 5 kilometers of shoreline. The file index is provided by the shape file, "md_boxes.shp", and the numbers used to identify files are in the "Box" field of the shape file. The LAS file naming convention is based on the year, project, area name, "Box," and the product type. An example file name is "2010_NCMP_MD_Aug_03_GeoClassified.las", where 2010 is the year of data collection, NCMP is the project under which data were collected, MD is the area of data collection, 03 is the "Box" number and "GeoClassified" is the product type. The format of the file is LAS version 1.1.