2014 - 2015 USGS Lidar: Glacier Peak, WA

Glacier Peak area

Monte Cristo area

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.

This graphic displays the footprint for this lidar data set.

Link to the data set report.

This data source was used (along with the airborne GPS/IMU data) to georeference the LiDAR point cloud data.

This data source was used to assess the overall LiDAR point cloud data.

This data source was used to populate the LiDAR point cloud data.

This data source was used to refine airborne GPS positional accuracy during the calibration process.

LiDAR Pre-Processing:

1. Review flight lines and data to ensure complete coverage of the study area and positional accuracy of the laser points.

2. Resolve kinematic corrections for aircraft position data using kinematic aircraft GPS and static ground GPS data.

3. Develop a smoothed best estimate of trajectory (SBET) file that blends post-processed aircraft position with sensor head position and attitude recorded throughout the survey.

4. Calculate laser point position by associating SBET position to each laser point return time, scan angle, intensity, etc. Create raw laser point cloud data for the entire survey in *.las format. Convert data to orthometric elevations by applying a geoid12a correction.

5. Import raw laser points into manageable blocks (less than 500 MB) to perform manual relative accuracy calibration and filter erroneous points. Classify ground points for individual flight lines.

6. Using ground classified points per each flight line, test the relative accuracy. Perform automated line-to-line calibrations for system attitude parameters (pitch, roll, heading), mirror flex (scale) and GPS/IMU drift. Calculate calibrations on ground classified points from paired flight lines and apply results to all points in a flight line. Use every flight line for relative accuracy calibration.

7. Adjust the point cloud by comparing ground classified points to supplemental ground control points.

LiDAR Post-Processing:

1. Classify data to ground and other client designated classifications using proprietary classification algorithms.

2. Manually QC data classification

3. After completion of classification and final QC approval, calculate FVA, SVAs, CVA, and density information for the project using ground control quality check points.

The NOAA Office for Coastal Management (OCM) downloaded this data set from this USGS site:

ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/USGS_LPC_WA_GlacierPeak_2014_LAS_2016/

The number of files downloaded and processed was 1403.

The data were in UTM Zone 10N (NAD83 CORS96) coordinates in meters and NAVD88 (Geoid03) elevations in meters. The data were classified as: 1 - Unclassified, 2 - Ground, 7 - Low Noise, 9 - Water, 10 - Ignored Ground, 17 - Bridge Decks. OCM processed all classifications of points to the Digital Coast Data Access Viewer (DAV). Classes available on the DAV are: 1, 2, 3, 7, 9, 10, 17.

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

1. An internal OCM script was run to check the number of points by classification and by flight ID and the gps and intensity ranges.

2. Determined that file USGS_LPC_WA_GlacierPeak_2014_10UFU5240_LAS_2016.laz was corrupt. Used Global Mapper to delete ~2000 points that were horizontally off and 1 point that was classified as 26 that was vertically incorrect.

3. Internal OCM scripts were run on the laz files to convert from orthometric (NAVD88) elevations to ellipsoid elevations using the Geoid03 model, to convert from UTM Zone 10N (NAD83 CORS96) coordinates in meters to geographic coordinates, to assign the geokeys, to sort the data by gps time and zip the data to database and to http.