Data Management Plan

This digital elevation model (DEM) was created from a classified lidar point cloud encompassing the Colville National Forest project area, approximately 742 square miles. Each LAS/LAZ file contains LiDAR point information, which has been calibrated, controlled, and classified.

Ground Conditions: water at normal levels; no unusual inundation; no snow; leaf off

Process Steps:

• 2015-07-25 00:00:00 - Aerial LiDAR Acquisition: Aerial LiDAR was acquired, in sixteen (16) missions, using an ALS070HP SN7225 at an altitude of 2926 MSL to support a 8ppm^2 LiDAR point cloud. Airborne GPS and IMU data was collected during the acquisition and supported by LEICA SR530 GPS stations on NGS monuments K24, G483, and Z264. Data acquisition was completed between 8th of July through 25th of July 2015. Ground Control Survey: A survey was performed to support the acquisition of LiDAR collection. Ground GPS collection consists of collection NVA and VVA points for LiDAR validation in addition to control point GPS collection for flight support. All field survey observations were conducted between July 5, 2015 through July 25, 2015 using Leica SR530 and Topcon HiperV Dual Frequency GPS equipment, both configured to log data at 1 Hz, and at 10 degrees mask.
• 2015-07-31 00:00:00 - LiDAR Pre-processing: Airborne GPS and IMU data were merged to develop a Smoothed Best Estimate Trajectory (SBET) of the LiDAR system trajectory for each lift. LiDAR ranging data were initially calibrated using previous best parameters for this instrument and aircraft. Relative calibration was evaluated using advanced plane-matching analysis and parameter corrections derived. This process was repeated interactively until residual errors between overlapping swaths, across all project lifts, was reduced to 2 cm or less. Data were then block adjusted to match surveyed calibration control. Raw data NVA were checked using independently surveyed check points. Swath overage points were identified and tagged within each swath file
• 2015-08-11 00:00:00 - Initial processing of the GPS data was processed using Inertial Explorer. The solution file was generated and CloudPro software was used to generate georeferenced laser returns which were then processed in strip form allowing for the QC of the overlap between strips (lines). The data from each line were combined and automated classification routines run to determine the initial surface model. This initial surface model was then verified to the surveyed test points.
• 2015-08-16 00:00:00 - LiDAR Post-Processing: The calibrated and controlled LiDAR swaths were processed using automatic point classification routines in TerraSolid software. These routines operate against the entire collection (all swaths, all lifts), eliminating character differences between files. Data were then distributed as virtual tiles to experienced LiDAR analysts for localized automatic classification, manual editing, and peer-based QC checks. Supervisory QC monitoring of work in progress and completed editing ensured consistency of classification character and adherence to project requirements across the entire project. All classification tags are stored in the original swath files. After completion of classification and final QC approval, the NVA and VVA for the project are calculated. Sample areas for each land cover type present in the project were extracted and forwarded to the client, along with the results of the accuracy tests. Upon acceptance, the complete classified LiDAR swath files were delivered to the client.
• 2015-08-23 00:00:00 - LiDAR Classification: The calibrated LiDAR data was run through automated classification routines and then manually checked and edited. The data was classified into the following classes: Class Code:1 Class Item:Undetermined/Unclassified Class Code:2 Class Item:Bare EarthNoise
• 2015-08-25 00:00:00 - Bare-Earth DEM Creation: Bare-Earth Digital Elevation Models (DEMs) were derived using bare-earth (ground) LiDAR points. All DEMs were created with a grid spacing of 1 meter. The DEMs were cut to 7.5 quads index provided by client.
• 2023-02-15 00:00:00 - Digital elevation models were received from US Forest Service by NOAA Office for Coastal Management in ERDAS Imagine format. The files were converted to cloud optimized GeoTiffs for distribution in the Digital Coast Data Access Viewer. (Citation: Classified lidar data)

Data is available online for bulk or custom downloads

Data is backed up to tape and to cloud storage.