Summary

Description

These files contain classified topographic and bathymetric lidar data as unclassified valid topographic data (1), and valid topographic data classified as ground (2), Classes 1 and 2 are defined in accordance with the American Society for Photogrammetry and Remote Sensing (ASPRS) classification standards. These data were collected by the Coastal Zone Mapping and Imaging Lidar (CZMIL) system. CZMIL integrates a lidar sensor with topographic and bathymetric capabilities, a digital camera and a hyperspectral imager on a single remote sensing platform for use in coastal mapping and charting activities. Native lidar data is not generally in a format accessible to most Geographic 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) GEOID12A 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 a USGS quarter quad. The file index is provided by the shape file, NY_NJ_Tiles_NAD83.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, effort, area name, "Box," and the product type. An example file name is "2012_PostSandy_NY_000486_GeoClassifiedLAS.las", where 2012 is the year of data collection, PostSandy is the project under which data were collected, NY is the area of data collection, 000486 is the "Box" (quarter quad) number and "GeoClassified.las" is the product type. The format of the file is LAS version 1.2.