| description:
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Maine GeoLibrary LiDAR Project. Product: These are Digital Elevation Model (DEM) data for the Maine 2017 LiDAR QL2 - Delivery #2 area in Aroostook, Hancock, Penobscot, Piscataquis, Sagadahoc, Somerset, and Washington Counties, Maine as part of the required deliverables for the 2017 Maine LiDAR project. Class 2 (ground) lidar points in conjunction with the hydro breaklines were used to create 0.25-meter, 0.5-meter, and 1-meter hydro-flattened raster DEMs. Geographic Extent: Seven partial counties in Maine, covering approximately 9,314 total square miles. Dataset Description: Maine 2017 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 for counties in the eastern AOI was developed based on a horizontal projection/datum of NAD83 (2011) UTM Zone 19, meters and vertical datum of NAVD88 (GEOID12B), meters. LiDAR data was delivered as flightline-extent unclassified LAS swaths, as processed Classified LAS 1.4 files formatted to 11,133 individual 1,500-meter x 1,500-meter tiles, 63 individual 750-meter x 750-meter tiles, and 36 individual 500-meter x 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 hydro-flattened breaklines were produced in Esri file geodatabase format. 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. |
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["elevation","LiDAR","LiDAR derivative","surface","Digital Elevation Model","DEM","GeoLibrary","Maine","MaineGeoLibrary","MaineGIS","2017"] |