2015 DVRPC Lidar DEM: Delaware Valley - 5A (PA)

Original Dataset Geographic Extent: This data set is part of a larger collection of the Delaware Valley project that covers approximately 3260 square miles over the Philadelphia Metro area, comprised of of 8 contiguous counties located in the states of Pennsylvania and New Jersey. This data set was a re-flight, flown on November 25, 2015, after the initial collection of the larger data set in April 2015. This area was re-flown due to weather and leaf pop. This data set covers an area in Delaware, Montgomery, and Philadelphia Counties, PA.

Original 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.

Original Dataset 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 a total of 155 Land Cover control points that were used to calibrate the LIDAR to known ground locations established throughout the Delaware Valley project area (75 calibration control points).

This metadata record supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV). For this data set, the DAV is leveraging the GeoTIFF files hosted by USGS on Amazon Web Services.

Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create Breaklines and Raster. 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.

USGS Contract: G10PC00026 Task Order Number: G15PD00316 CONTRACTOR: Quantum Spatial Lidar data were acquired and calibrated by Quantum Spatial. All follow-on processing was completed by the prime contractor.

Any conclusions drawn from the analysis of this information are not the responsibility of DVRPC, USGS, NOAA, the Office for Coastal Management or its partners.

Data is available online for bulk and custom downloads.

None

Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations.

MicroStation Version 8; TerraScan Version 15; TerraModeler Version 15; GeoCue Version 2014.1.21.1; ESRI ArcGIS 10.2; Global Mapper 16; Leica Cloud Pro 1.2; Windows 7 Operating System

\\psihq_nx3200\Projects\26236_DVRPC_LiDAR\ 24.1 GB and

\\Matrix\LIDAR\26236_DVRPC\ 5.09 TB

The tested Non-Vegetated Vertical Accuracy (NVA) for the dataset captured from the DEM using bi-linear interpolation to derive the DEM elevations was found to be 0.041 m in terms of the RMSEz. The resulting accuracy stated as the 95% confidence level (RMSEz x 1.96) is 0.080 m. This dataset meets the required NVA of less than or equal to 19.6 cm at the 95% confidence level (based on NSSDA).

The tested Vegetated Vertical Accuracy (VVA) for the dataset captured from the DEM using bilinear interpolation for all classes (including the bare earth class) was found to be 0.265 m, which is stated in terms of the 95th percentile error. Therefore the data meets the required VVA of less than or equal to 29.4 cm. This test was based on the 95th percentile error (based on ASPRS guidelines) across all land cover categories.

These raw LAS data files include all data points collected. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. No void areas or missing data exist. The raw point cloud is of good quality and data passes Nonvegetated Vertical Accuracy specifications.

Data cover the entire area specified for this project.

Data is backed up to tape and to cloud storage.

The NOAA Office for Coastal Management (OCM) ingested references to the USGS GeoTIFF files that are hosted on Amazon Web Services (AWS), into the Digital Coast Data Access Viewer (DAV). The DAV accesses the raster data as it resides on AWS.