2018 - 2020 NOAA USGS Lidar: Hawaii, HI

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.

Project report by the contractor. Describes the project and data prior to any NOAA changes.

Geospatial features indicating where there is low confidence in the ground values.

Full list of contributors still needs to be added.

Lidar Point Cloud Classification: The Single Photon Lidar (SPL) data acquisition was acquired at a density greater than the task order specified density of QL1 or 8 points per square meter. USGS and NOAA agreed the density of the data should be reduced to provide a more manageable data set. The data was decimated to provide a density not less than 8 points per square meter, however due to significant overlap of acquisition flight lines in some areas of the project, the density in some cases exceeds 8 points per square meter. The Single Photon Lidar (SPL) data acquisition occurred between multiple acquisition seasons creating significant data overlap between seasons. To reduce excessive density, the data was processed to eliminate excess overlap in these areas. The point cloud underwent a classification process to determine bare-earth points and non-ground points utilizing "first and only" as well as "last of many" lidar returns. This process determined Processed, but Unclassified (Class 1), Bare Earth Ground (Class 2), Vegetation (Class 5), Low Noise (Class 7), Water (Class 9), Ignored Ground (Class 10), Bridge Decks (Class 17), and High Noise (Class 18). The bare-earth (Class 2 - Ground) lidar points underwent a manual QA/QC step to verify the quality of the DEM as well as a peer-based QC review. This included a review of the DEM surface to remove artifacts and ensure topographic quality.

After the bare-earth surface is finalized, it is then used to generate all hydro-breaklines through a semi-automated process. All ground (Class 2) lidar data inside of the Lake Pond and Double Line Drain hydro flattening breaklines were then classified to water (Class 9) using TerraScan/LP360 macro functionality. A buffer of 0.7 meters was also used around each hydro-flattened feature to classify these ground (Class 2) points to Ignored ground (Class 10). All Lake Pond Island and Double Line Drain Island features were checked to ensure that the ground (Class 2) points were reclassified to the correct classification after the automated classification was completed. These classes were created through automated processes only and were not verified for classification accuracy. Due to software limitations within TerraScan, these classes were used to trip the withheld bit within various software packages. These processes were reviewed and accepted by USGS through numerous conference calls and pilot study areas.

The single photon lidar data acquisition for this award occurred across two separate deployments. The approximate date range of the first acquisition window was from January 2018 to March 2018 and second window was from November 2019 to January 2020. Given the complexity of the terrain, the flight plan for the project included significant overlapping and off-angle lines between the 2018 and 2019/2020 collection which can create more opportunity to notice differences than is normally seen in a lidar collection where lines tend to follow a single direction and acquisition across years is cut into more complete blocks. For each acquisition season, the acquired data was processed and geometrically calibrated by Woolpert's teaming and data acquisition partner Hexagon. During the calibration, the data was processed to meet the required accuracy specifications per each mission as well as between adjacent missions of the differing flight dates within a given acquisition season. Once the calibration was complete and the data entered full processing, Woolpert made the best efforts to populate delivery tiles containing flights from different acquisition seasons with data acquired from a single season. In these tiles preference was given to the points acquired during the 2018 season because of the significant data processing had occurred within these tiles prior to the second acquisition season. In some areas pieces of lines from the different acquisitions created the edge artifacts. Low confidence polygons were generated around these areas to make the user aware of the discrepancy. All data was manually reviewed and any remaining artifacts removed using functionality provided by TerraScan and TerraModeler. Global Mapper was used as a final check of the bare earth dataset. GeoCue was then used to create the deliverable industry-standard LAS files. Woolpert proprietary software and LP360 was used to perform final statistical analysis of the classes in the LAS files, on a per tile level to verify final classification metrics and full LAS header information.

NOAA Office for Coastal Management received the classified point cloud data from Woolpert in Orthometric (Geoid12b) NAD83(PA11) UTM zone 5 coordinates with units of meters. An examination of the histograms of height by class indicated that some issues with low points. The withheld points were removed as being geometrically unreliable. In addition, all points below -30 meters were reclassed to low noise (class 7).

Data were converted to geographic coordinates in ellipsoid heights for use in the Data Access Viewer.

The point clouds for two tiles (5QKB800850.laz and 5QKB810850.laz) were re-examined to find ground points near the cliffs. The lack of ground points identified near the edge caused issues in DEM generation as the TIN process was cutting off the cliffs. This work was done by the original lidar contractor, Woolpert. The original tiles were replaced with the new tiles.