Data Management Plan

This bare earth hydro flattened digital elevation model (DEM) represents the earth's surface with all vegetation and human-made structures removed and hydro flattening performed within the OLC Santiam defined project area. Bare Earth Hydro Flattened DEMs were derived from LiDAR data using TIN processing of the ground point returns. The DEM grid cell size is 1 meter. The dataset encompasses 110,378 acres within Polk County and Marion County in Oregon. The nominal pulse density is eight pulses per square meter. The bare earth (BE) digital elevation model (DEM) raster grid cell size is 3 feet. The native projection is Oregon Statewide Lambert, Lambert Conformal Conic, units are in international feet. The native horizontal datum is NAD83(2011) and the native vertical datum is NAVD88 (Geoid 12B). Quantum Geospatial Inc. collected the lidar and created this dataset for the Oregon Department of Geology and Mineral Industries (DOGAMI).

A link to the points and hydro-breaklines used to create this DEM can be found in the Related Items and URL sections, below.

Process Steps:

• 2018-11-21 00:00:00 - 1. TRAJECTORY: Aircraft trajectory (position and attitude) were calculated based on on-board GPS and IMU data with post-processing refinement through coincident static GPS collection. 2. POST-PROCESSING: Laser point return coordinates (x,y,z) were computed using sensor-specific post processing software, combining LiDAR return range and intensity information with aircraft trajectory information. 3. INITIAL QAQC: The post-processed LiDAR files were assembled into flight lines and reviewed for gaps and consistency, as well as systematic noise. 4. CALIBRATION: Custom algorithms evaluated individual swaths for misalignments based on IMU configuration as well as aircraft attitude variability. Offsets were resolved through surface and linear matching algorithms that minimize variability in elevation and slope. Descriptive statistics, thresholds, and specifications providing transparency for data calibration are discussed in the accompanying Data Report. 5. GROUND MODELING: Ground classified point cloud was generated through proprietary data processing tools, with settings and thresholds appropriate to landscape and vegetation condition. 6. ARTIFACT FILTRATION: Noise and processing artifacts were filtered using post-processing software and proprietary quality control methods. 7. ACCURACY ASSESSMENT: Vertical accuracy for the LiDAR dataset was assessed against reserved Quality Assurance Points (QAPs) distributed throughout the study area and not used during calibration processes. See the accompanying Data Report for methodology, descriptive statistics, and relevant standards and reporting language. 8. DATA PRODUCT: LiDAR points classified as 'ground' were output as a digital elevation model (DEM). 9. Hydro Flattening Breakline Processing: Class 2 LiDAR was used to create a bare earth surface model. E-Cognition utilized rasters created within Bentley Microstation to auto-generate breaklines of inland streams and rivers with a 100 foot nominal width and Inland Ponds of 2 acres or greater surface area. Breaklines for Lakes with surface area greater than 2 acres were generated using heads-up digitization. Elevation values were assigned to all Inland Ponds and Lakes within ESRI ArcMap; Inland Pond and Lake Islands, Inland Stream and River Islands were assigned elevation values from within ESRI ArcMap. All ground (ASPRS Class 2) LiDAR data inside of the collected inland breaklines were then classified to water (ASPRS Class 9) using TerraScan macro functionality. A buffer of 2.1 meter was also used around each hydro-flattened stream. These points were moved from ground (ASPRS Class 2) to Ignored Ground (ASPRS Class 10). The breakline files were then translated to ESRI File-Geodatabase format using ESRI conversion tools.
• 2019-10-11 00:00:00 - Data was obtained by NOAA Office for Coastal Management from DOGAMI. Data were in Oregon Lambert NAD83(HARN) international feet with NAVD88(Geoid03) international feet vertically. Data were in ArcGrid proprietary format and were converted to GeoTiff format using GDAL 2.4.0 to comply with the open data policy and for ingest into the Digital Coast Data Access Viewer.

Data is available online for custom downloads