Product: These LiDAR data are 36 classified LAS 1.4 files; used to create intensity images, 3D breaklines and hydro-flattened DEMs as necessary.
Geographic Extent: Merrymeeting Bay, ME in Sagadahoc County, covering approximately 2 square miles.
Data set Description: This data set covers a small area in southern Maine, that was collected at the same time as a much larger data set in eastern Maine, but is provided at 16 points per square meter. There is also a data set for the same area that is provided at 8 points per square meter. See the Related Items section of this metadata record for a link to that data set metadata record. Additionally, the hydro breaklines and the Digital Elevation Model (DEM) data created from these 36 lidar files are also available. See the URL section of this metadata record for a link to the hydro breaklines and the Related Item section for a link to the DEM data metadata record. A link to metadata for the larger data set, 2017 Lidar: Eastern Maine, is also provided in the Related Item section.
The 2017 Eastern Maine 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 was developed based on a horizontal projection/datum of NAD83 (2011) UTM Zone 19, meters and vertical datum of NAVD88 (GEOID12B), meters.
Ground Conditions: LiDAR was collected in the spring and fall of 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. established a total of 181 ground control points that were used to calibrate the LiDAR to known ground locations established throughout the project area. An additional 301 independent accuracy checkpoints, 178 in Bare Earth and Urban landcovers (178 NVA points), 123 in Forested, Shrubs, and Tall Weeds categories (123 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.
This data set is an LAZ (compressed LAS) format file containing LIDAR point cloud data.