Geographic Extent: Delaware Valley, covering approximately 3260 square miles over the Philadelphia Metro area, comprised of of 8 contiguous counties located in the states of Pennsylvania and New Jersey. Dataset Description: Delaware Valley 2015 LiDAR project called for the Planning, Acquisition, processing and derivative products of LIDAR data to be collected at a nominal pulse spacing (NPS) of 0.7 meter. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base LIDAR Specification, Version 1.2. The data was developed based on a horizontal projection/datum of UTM Zone 18, NAD83 (2011), meters and vertical datum of NAVD1988 (GEOID12A), meters. LiDAR data was delivered in RAW flight line swath format, processed to create Classified LAS 1.4 Files formatted to 25 individual 1500 meter X 1500 meter tiles for the pilot (3752 individual 1500 meter X 1500 meter tiles for the entire project area), Bare Earth DEMs tiled to the same 1500 meter X 1500 meter tile schema, and Breaklines in Esri shapefile format. Ground Conditions: LiDAR was collected in spring of 2015, while no snow was on the ground and rivers were at or below normal levels. In order to post process the LiDAR data to meet task order specifications, Quantum Spatial established 76 calibration control points in order to calibrate the LIDAR to known ground locations established throughout the Delaware Valley project area. The accuracy of the data was checked with 91 NVA points and 70 VVA points (161 total QC checkpoints).
Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create Breaklines and Raster DEMs. The purpose of these lidar data was to produce high accuracy 3D hydro-flattened Digital Elevation Model (DEM) with a 1-meter cell size. These raw lidar point cloud data were used to create classified lidar LAS files, 3D breaklines, and hydro-flattened DEMs as necessary.