2009 Federal Emergency Management Agency (FEMA) Topographic LiDAR: Fort Kent, Maine

Camp Dresser McKee Inc. contracted with Sanborn Map Company to provide LiDAR mapping services for Fort Kent, Maine. Utilizing multi-return systems, Light Detection and Ranging (LiDAR) data in the form of 3-dimensional positions

of a dense set of mass points was collected in spring 2009 for 187 square miles along the St. Johns River and the Fish River. The Leica ALS-50 LiDAR system was used to collect data for the survey campaign.

The nominal point spacing of this data set is 1.4 meters.

Leica ALS-50 LiDAR System Acquisition Parameters:

Average Altitude: 1400 Meters above ground level

Airspeed: ~120 Knots

Scan Frequency: 36 Hertz

Scan Width Half Angle: 20 Degrees

Pulse Rate: 76,200 Hertz

LiDAR points used in conjunction with LiDAR derived breaklines to determine a DTM surface.

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A footprint of this data set may be viewed in Google Earth at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/2481/supplemental/me2009_fema_fortkent_footprint.KMZ

A survey report for this data set may be viewed in PDF format at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/2481/supplemental/me2009_fema_fortkent_surveyreport.pdf

LiDAR points in LAS 1.1 format

The Survey Report referenced in the Supplemental_Information section above contains a detailed description of the data themes and references to other relevant information.

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

of Camp Dresser McKee Inc, Sanborn Map Company, FEMA, NOAA, the Office for Coastal Management or its partners.

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

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=2481

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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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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. These data depict the heights at the time of the survey and are only accurate for that time.

Lidar acquired and processed to meet 1m (RMSE) horizontal accuracy.; Quantitative Value: 1.0 meters, Test that produced the value:

Units in meters. Horizontal point accuracy is a function of angular origination of the pulse; IMU orientation; the scanner encoder and ranging function and will vary depending on the proposed point density selected for the collection.

Statistically, the error is roughly 1/3 of the illuminated foot print on the ground and is a function of the beam divergences.

The vertical accuracy is based on the Sanborn independent collection of 20 ground survey points distributed throughout the project. The RMSEz of all survey checkpoints tested as .195 ft (6 cm).; Quantitative Value: 0.06 meters, Test that produced the value: Tested RMSEz. Units in meters.

A visual qualitative assessment was performed in the source Lidar dataset. Small data voids were noted by NOAA OCM in tiles 1275-16750 and 1225-17000, these voids are over water and should

not impact the quality of the data set.

Data covers the tile scheme provided for the area of interest.