2018 OLC Lidar DEM: Santiam, OR

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.

This dataset provides high resolution elevation data that is used to produce three-dimensional models of the earth surface for the purpose of managing natural resources and mapping natural hazards.

The data were collected for the Oregon Department of Geology and Mineral Industries by Quantum Spatial Inc. under State of Oregon Agency-Specific Price Agreement 7525. The price agreement specifies in Section 2.2 that the Quantum Spatial Inc. provide classified LAS files, intensity grids, digital elevation models (DEMs), digital surface models (DSMs), vector files, and a survey report.

Users should be aware that temporal changes may have occurred since this dataset was collected and that some parts of these data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations. This product is for informational purposes and may not have been prepared for or be suitable for legal, engineering, surveying, or site specific purposes. Users of this information should review or consult the primary data and information sources to ascertain the usability of the information. Acknowledgement of Oregon Department of Geology and Industries (DOGAMI) would be appreciated for products derived from these data.

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners

Data is available online for custom downloads

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Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations.

LiDAR Mapping Suite 2.4, Applanix PosPac 7.1, Microstation Version 8.0, TerraScan Version 16, TerraModeler Version 16, TerraMatch Version 16, ESRI ArcGIS 10.3.1, Windows 7 Operating System

State of Oregon Agency-Specific Price Agreement 7525 required that Quantum Spatial Inc. calculate fundamental vertical accuracy of lidar point data by comparing ground survey points (GSPs) on flat surfaces in areas where ground classified point resolution is both high, and the ground surface is open, smooth and without vegetation, to a local triangulated irregular network (TIN) surface of ground classified points. The fundamental vertical accuracy did not exceed 9.25 cm RMSE.Qualitative value:0.022 m RMSE, Test that produced the value: The vertical accuracy was tested using 20 reserved ground survey points (GSPs), or quality assurance points (QAPs) located in open terrain. The QAPs were uniformly distributed throughout the project area. The 20 QAPs were established using GPS or other techniques that result in vertical and horizontal accuracies of 1.5 cm root-mean-square-error (RMSE) or better. Vertical accuracy was assessed by QSI by calculating and averaging the distances between GSPs that are not clustered and a surface interpolated from lidar first returns. The RMSE was computed to be 2.20 centimeters as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines.

A visual qualitative assessment was performed to ensure data completeness. No void areas or missing data exist.

Data covers the entire area specified for this project.