Product: Contours with a 2-foot interval in Esri file shapefile format.
Geographic Extent: 13 counties in Pennsylvania, covering approximately 6,602 total
square miles. Dataset Description: The South Central Pennsylvania 2017 QL2 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 meters. Project
specifications are based on the U.S. Geological Survey National Geospatial Program
Base LiDAR Specification, Version 1.2. The data were developed based on a horizontal
projection/datum of NAD 1983 (2011), UTM Zone 18, meters and vertical datum of NAVD
1988 (GEOID 12B), meters. LiDAR data were delivered as processed Classified LAS 1.4
files formatted to 7,975 individual 1,500-meter x 1,500-meter tiles, as tiled
intensity imagery, and as tiled bare earth DEMs; all tiled to the same 1,500-meter x
1,500-meter schema. Continuous breaklines were produced in Esri file geodatabase
format. Ground Conditions: LiDAR was collected in fall 2017, 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 and meet ASPRS vertical accuracy
guidelines, Quantum Spatial, Inc. utilized a total of 150 ground control points that
were used to calibrate the LiDAR to known ground locations established throughout
the project area. An additional 245 independent accuracy checkpoints, 142 in Bare
Earth and Urban landcovers (142 NVA points), 103 in Tall Weeds categories (103 VVA
points), were used to assess the vertical accuracy of the data. These checkpoints
were not used to calibrate or post process the data.
To acquire detailed surface elevation data for use in conservation planning, design, research, floodplain mapping, dam safety assessments and elevation modeling, etc. Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create intensity images, breaklines and raster DEMs. The purpose of these LiDAR data was to produce high accuracy 3D hydro-flattened digital elevation models (DEMs) with a 1-meter cell size. These raw LiDAR point cloud data were used to create classified LiDAR LAS files, intensity images, 3D breaklines, and hydro-flattened DEMs as necessary.