2009 Aero-Metric Inc. Topographic LiDAR: Yukon Flats, Alaska
This kmz file shows the extent of coverage for the 2009 Yukon Flats, Alaska lidar
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
Cite this dataset when used as a source.
|Search and Download
|| Distributor information not available
| Point of Contact
||National Oceanic and Atmospheric Administration (NOAA)
Documentation links not available.
|Data Presentation Form:
|| Digital image
|Dataset Progress Status
|Data Update Frequency:
|| As needed
||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.
|| Unknown to Unknown
|Spatial Reference System:
|Spatial Bounding Box Coordinates:
|Spatial Coverage Map:
- Remote Sensing
| Use Constraints
|| No constraint information available
|| Fee information not available.
|| Lineage statement not available.
| Processing Steps
- Create a smoothed-best estimated trajectory (SBET) of the sensor at a rate of 200
Hz, by integrating the airborne GPS and IMU data The basis of the GPS coordinates
were established using OPUS, and were referenced to NAD83 (CORS96) with ellipsoidal
heights. The mean GPS positional accuracy for this area was +/- 0.08 meters.
- Integrate SBET and raw laser data to produce point cloud data in LAS 1.2 format for
each flight line.
- Compute the roll, pitch, heading, and mirror scale correction factors for each flight
line, then apply corrections to the corresponding flight line.
- Automated classification of the bare-earth data from the lidar point cloud using a
series of algorithms customized for the types of terrain encountered in the project.
- Manual classification of any data which appears to be bare-earth but was not properly
classified using the automated methods.
- Create point clouds in LAS 1.2 format for all returns with GPS week timstamps.
- Convert point clouds with GPS week timestamps, to point clouds with absolute GPS timestamps,
in LAS 1.2 format.
- Data verified using survey control points, located throughout the area.
- The NOAA Coastal Services Center (CSC) received topographic files in LAS 1.2 format.
The files contained lidar elevation and intensity measurements. The data were received
in projected coordinates of NAD83 UTM6N, meters and were vertically referenced to
NAVD88 orthometric elevations using GEOID06(Alaska). The vertical units of the data
were meters. CSC performed the following processing for data storage and Digital Coast
provisioning purposes: 1. The topographic las files were converted from Projected
Coordinates (NAD83 UTM6N, meters) to Geographic Coordinates (NAD83, decimal degrees).
2. The topographic las files were vertically converted from orthometric elevations
(NAVD88) to ellipsoidal elevations (NAD83) with GEOID06. 3. The data were converted
to LAZ format.
- The NOAA National Geophysical Data Center (NGDC) received lidar data files via ftp
transfer from the NOAA Coastal Services Center. The data are currently
being served via NOAA CSC Digital Coast at http://www.csc.noaa.gov/digitalcoast/.
The data can be used to re-populate the system. The data are archived in LAS or LAZ
The LAS format is an industry standard for LiDAR data developed by the American Society
of Photogrammetry and Remote Sensing (ASPRS); LAZ is a loseless compressed version
LAS developed by Martin Isenburg (http://www.laszip.org/). The data are exclusively
in geographic coordinates (either NAD83 or ITRF94). The data are referenced vertically
the ellipsoid (either GRS80 or ITRF94), allowing for the ability to apply the most
up to date geoid model when transforming to orthometric heights.
Metadata Last Modified: 2013-04-25
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