2013 UAF/GINA Lidar: Arctic Coastal Plain, AK

Create custom data files by choosing data area, product type, map projection, file format, datum, etc. A new metadata will be produced to reflect your request using this record as a base. Change to an orthometric vertical datum is one of the many options.

Bulk download of data files in LAZ format, geographic coordinates, orthometric heights. Note that the vertical datum (hence elevations) of the files here are different than described in this document. They will be in an orthometric datum.

The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer.

Link to view the point cloud (using the Entwine Point Tile (EPT) format) in the 3D Potree viewer.

Entwine Point Tile (EPT) is a simple and flexible octree-based storage format for point cloud data. The data is organized in such a way that the data can be reasonably streamed over the internet, pulling only the points you need. EPT files can be queried to return a subset of the points that give you a representation of the area. As you zoom further in, you are requesting higher and higher densities. A dataset in EPT will contain a lot of files, however, the ept.json file describes all the rest. The EPT file can be used in Potree and QGIS to view the point cloud.

This graphic displays the footprint for this lidar data set.

Link to custom download, from the Data Access Viewer (DAV), the raster Digital Elevation Model (DEM) data that were created from this lidar data set.

Created 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 two dual frequency GPS receivers, collecting data at a rate of 2 Hz operated by Aero-Metric during the acquisition phase of this project, and were referenced to to NAD83 (CORS96) ellipsoid heights.

Integrated SBET and raw laser data to produce point cloud data in LAS 1.2 format for each flight line.

Processed data calibration: An in-situ calibration was performed using the data collect for this project. The data was classified in each line separately for ground and other common features between lines, such as building roofs. This data was processed in TerraMatch 11.001 (TerraSolid, Ltd.), to compute corrections for roll, pitch, heading, and mirror scale. These corrections are applied in order to minimize discrepancies between flight lines.

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.

Manually classified any data which appears to be improperly classified using the automated methods.

Created classified point cloud data, in LAS 1.2 format.

The NOAA Office for Coastal Management (OCM) downloaded 1804 laz files from the Alaska Division of Geological and Geophysical Surveys Elevation Portal (https://elevation.alaska.gov/). The files contained classified elevation and intensity measurements for the 2013 Coastal Plain project. The data were in AK State Plane Zone 4 NAD83 (2011), meters coordinates and NAVD88 (GEOID12A) elevations in meters. The data had the following classifications: 1 - Unclassified, 2 - Ground, 3- Low Vegetation, 6 - Buildings, 7 - Noise, 8 - Model Key Point, 9 - Water, 10 - Breakline Proximity. OCM processed all points to the Digital Coast Data Access Viewer (DAV). The metadata and the report said that there were Class 13 points (Bridges), but the OCM internal script to check the point classifications, resulted in 0 points with that classification.

OCM performed the following processing on the data for Digital Coast storage and provisioning purposes:

1. Internal OCM scripts were run to check the number of points by classification and by flight ID and the gps and intensity ranges.

2. Internal OCM scripts were run on the laz files to convert from AK State Plane Zone 4 NAD83 (2011) meters coordinates to geographic coordinates, to convert from NAVD88 elevations to ellipsoid elevations using the GEOID12A model, to assign the geokeys, to sort the data by gps time and zip the data to database and to the AWS S3 bucket.