2009 Aero-Metric Inc. Topographic LiDAR: Yukon Flats, Alaska

This delivery contains point cloud data in LAS 1.2 format, classified in the following manner. Class 1: Unclassified and Class 2: Ground. Overlap points have been flagged as withheld. The timestamps are in absolute

GPS time minus 1 billion, in accordance with the LAS 1.2 documentation.

The following are the collection parameters and equipment used to create this data set.

Aircraft: Piper Navajo (N6GR)

Lidar System: Optech ALTM Gemini (03SEN145)

Approximate Collection Altitude (Above Mean Terrain): 3800 meters

Ground Speed: 160 kts

Pulse Rate Frequency: 33 kHz

Mirror Scan Frequency: 18 Hz

Scan Angle (+/-): 16 degrees

Beam Divergence: Narrow (0.25 mrad)

Scan Cutoff: 0.02 degrees

Accuracy statements are based on areas of moderate terrain, with points classified as ground. Diminished accuracies are to be expected in areas of extreme terrain and dense vegetation. The accuracy of each point is expected to

meet the vertical accuracy standard, derived products may be less accurate in areas of extreme terrain and dense vegetation due to a lesser number of points defining the ground in these areas.

Classified data sets such as this one may have varying posting due to some pulses not reaching the ground.

Original contact information:

Contact Name: Jacques Cloutier

Contact Org: Aero-Metric, Inc.

Title: Senior Geodetic Surveyor

Phone: (907) 272-4495

Email: aerometric@aerometric-ak.com

The purpose of this data set is to provide bare-earth processed lidar data over the project area Southwest of Fort Yukon, at an average point spacing of 2.3 meters.

10266

Unclassified Lidar point cloud in LAS 1.2 format

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

of Aero-Metric Inc, 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=1467

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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and some parts of this data may no longer represent actual surface conditions.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.

All these data products were acquired at 3800 meters above mean terrain (AMT) and have a horizontal accuracy of 1.15 meters, with a nominal point spacing of 2.3 meters as per manufacturer's specifications, not field verified.; Quantitative Value: 1.15 meters, Test that produced the value: Compiled to meet value (meters)

These values were computed by verifying the ground classified lidar data against ground surveyed points at the Fort Yukon airport. The points were collected throughout the project area by John Seibert of Pro Survey Services.

We recommend additional ground truth surveys of the data set to verify the vertical accuracy has not changed due to natural causes, such as techtonic motion or freeze/thaw cycles, and non-natural causes such as road construction.

Without ground truth survey checks this data is not recommended for design grade mapping or engineering.

; Quantitative Value: 0.10 meters, Test that produced the value: Consolidated vertical accuracy at the 95th percentile along road and runway surfaces (meters).

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Data has been verified using surveyed check points around the Fort Yukon Airport within the project area. All data was collected to meet the National Standard for Spatial Database Accuracy (NSSDA).