Maine and Massachusetts 2015 QL1 and QL2 Lidar DEM

Geographic Extent:

Central Maine, covering approximately 2,882 total square miles at QL 2.

Western Massachusetts, covering approximately 815 total square miles at QL 1.

Western Massachusetts, covering approximately 2,770 total square miles at QL 2.

Dataset Description:

The Maine and Massachusetts 2015 QL1 and QL2 LiDAR project called for the Planning, Acquisition, processing and derivative products of LIDAR data to be collected at an aggregate nominal pulse spacing (NPS) of 0.7 meters for the 5652 square miles of the QL2 Maine and Massachusetts AOIs, and an NPS of 0.35 meters for the 815 square miles of the QL1 Massachusetts AOI. 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 Zones 18 and 19, meters and vertical datum of NAVD88 (GEOID12A), meters. The application of GEOID12A was subsequently reversed for storage in the Digital Coast Data Access Viewer resulting in ellipsoid heights instead of NAVD88. Lidar data was delivered in RAW flight line swath format, processed to create Classified LAS 1.4 Files formatted to individual 1,500 meter X 1,500 meter tiles for the QL2 data and 750 meter X 750 meter tiles for the QL1 data. Corresponding 1-meter Intensity Image and 1-meter Bare Earth DEM tiles were created with the same tile schema. Breaklines were produced in Esri shapefile format.

Ground Conditions:

Lidar was partially collected in spring of 2015 and completed in winter 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 286 Land Cover control points in Maine, 255 Land Cover control points in Massachusetts UTM zone 18 and 29 Land Cover control points in Massachusetts zone 19. These were used to calibrate the LIDAR to known ground locations established throughout the entire dataset as follows:

Maine: 136 calibration control points and 150 QC checkpoints.

Massachusetts zone 18: 122 calibration control points and 133 QC checkpoints

Massachusetts zone 19: 17 calibration control points and 22 QC checkpoints

Original contact information:

Contact Org: National Oceanic and Atmospheric Administration (NOAA)

Title: Coastal Services Center

Phone: (843) 740-1200

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

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, intensity images, 3D breaklines and hydro-flattened DEMs as necessary.

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USGS Contract: G10PC00026 Task Order Number: G15PD00281

CONTRACTOR: Quantum Spatial

Lidar data were acquired and calibrated by Quantum Spatial, Atlantic, and Precision Aerial Reconnaissance.

Follow-on processing was completed by the prime contractor. Processing to ingest this data into the Digital Coast was completed by NOAA.

Supplemental reports can be found at https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/5087/supplemental/

Any conclusions drawn from the analysis of this information are not the responsibility

of Quantum Spatial, the States of Maine or Massachusetts, USGS, the NOAA Office for Coastal Management, or their partners.

This data can be obtained on-line at the following URL:

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=5191

The point cloud for this data can be obtained on-line at:

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=5087

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No restrictions apply to this data.

None. However, users should be aware that temporal changes may have occurred since this dataset was collected and that some parts of these data may no longer represent actual surface conditions. Users should not use these data for critical applications without a full awareness of its limitations. Acknowledgement of the U.S. Geological Survey would be appreciated for products derived from these data. Acknowledgement of the NOAA Digital Coast would be appreciated for their role in data distribution.

None.

None.

The specifications require that Nonvegetated Vertical Accuracy (NVA) be computed for raw lidar point cloud swath files. The vertical accuracy was tested with 84, 73, and 13 independent surveys located in open terrain for Maine, Massachusetts zone 18, and Massachusetts zone 19 respectively. These check points were not used in the calibration or post processing of the lidar point cloud data. The survey check points were distributed throughout the project. Specifications for this project require that the NVA be 19.6 cm or better AccuracyZ at 95 percent confidence level.

The Raw Non-Vegetated Vertical Accuracy (Raw NVA) for the dataset based on TINs derived from the final calibrated and controlled LiDAR swath data is stated in terms of the RMSEz and the 95% confidence level (RMSEz x 1.96) is listed below . This dataset meets the required NVA of = 19.6 cm at the 95% confidence level (according to the National Standard for Spatial Database Accuracy (NSSDA)).

Mass UTM18: RMSEz = 0.071 m (95% Confidence Level = 0.138 m)

Mass UTM 19: RMSEz = 0.023 m (95% Confidence Level = 0.045 m)

Maine UTM19: RMSEz = 0.039 m (95% Confidence Level = 0.076 m)

The tested Non-Vegetated Vertical Accuracy (NVA) for the dataset captured from the DEM using bi-linear interpolation to derive the DEM elevations is stated in terms of the RMSEz as well as the 95% confidence level (RMSEz x 1.96) are listed in Table 8 below. This dataset meets the required NVA of = 19.6 cm at the 95% confidence level (based on NSSDA). Please note that Point UA02 of the MA 18 AOI was not used in these calculations.

Mass UTM18: RMSEz = 0.070 m (95% Confidence Level = 0.138 m)

Mass UTM 19: RMSEz = 0.026 m (95% Confidence Level = 0.050 m)

Maine UTM19: RMSEz = 0.038 m (95% Confidence Level = 0.075 m)

The tested Vegetated Vertical Accuracy (VVA) for the dataset captured from the DEM using bi-linear interpolation for all classes (including the bare earth class) is stated in terms of the 95th percentile error are listed in Table 9 below. The data meets the required VVA of = 29.4 cm. Please note that points SW05 and SW08 were not used in the MA UTM 18 calculations.

Mass UTM18: RMSEz = 0.155 m (95% Confidence Level = 0.287 m)

Mass UTM 19: RMSEz = 0.064 m (95% Confidence Level = 0.107 m)

Maine UTM19: RMSEz = 0.145 m (95% Confidence Level = 0.286 m)

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. Points with elevation values lower than -40 meters ellipsoid height were removed from the data set.

Data cover the entire area specified for this project.