2010 USACE Lidar: Columbia River (OR, WA, ID, MT)

The Columbia River Light Detection and Ranging (LiDAR) survey project was a collaborative effort to develop detailed high density LiDAR terrain data for the US Army Corps of Engineers (USACE). The LiDAR will be used to support hydraulic modeling work associated with proposed 2014 Columbia River treaty negotiations. The dataset encompasses approximately 2836 square miles of territory in portions of Oregon, Washington, Idaho and Montana within the Columbia River drainage. This survey was under the jurisdiction of three Corps districts: Portland (CENWP), Seattle (CENWS), and Walla Walla (CENWW). CENWP was the project lead and primary contracting organization.

Bare earth point data are classified as either ground (2), model key point (8) or water (9) and represent the earth's surface with all vegetation and human-made structures removed. Model key points were generated to represent the bare earth surface within a 0.07 m tolerance. Ground points (class 2) are the remaining ground points not classed as model key. Both ground and model key classes are needed for display of all bare earth points. Water classification was used for those bare earth/ground classified points that fell inside a water boundary as determined using softcopy photogrammetry with stereograms generated from LiDAR intensities. All remaining points received the default classification (1). In some areas of heavy vegetation or forest cover, there may be relatively few ground points in the LiDAR data.

The RMSE of the data for open, hard-packed surfaces is 0.046 meters as assessed from 40,266 ground survey (real time kinematic) points taken on hard-packed road surfaces. This value is representative of anticipated accuracies in open, evenly sloped or flat terrain where maximum point densities were achieved.

The project was completed for the US Army Corps of Engineers, Portland District, to support hydraulic modeling related to the ACOE Columbia River Treaty project. Data acquisition, bare earth processing, and development of final tiled LiDAR deliverables and DEM's was performed by Watershed Sciences, Inc. Overall project management, photogrammetric quality control review using LiDAR stereograms, water delineation and breakline development was performed by David C. Smith & Associates, Inc. Professional Surveyor oversight of ground control data, ground control data processing and ground control publication was performed by David Evans and Associates, Inc. Final quality control review in ArcGIS of all final deliverables, including preparation of point density rasters and reach based geo-databases incorporating all deliverables, was performed by CC Patterson and Associates.

NOTE ON DATUM ISSUES: All ground control and subsequent LiDAR data deliverables were developed and delivered at NAD '83 CORS 96 horizontal and NAVD '88 Geoid '09 vertical datums as processed in OPUS-DB. Due to limitations in the transformations supported by ESRI, NAD '83 and NAVD '88 datums were temporarily assigned to the ESRI deliverables and ESRI .prj file even though the actual coordinate values in the data files are at the original NAD '83 CORS 96 and NAVD '88 Geoid '09 datums. In many instances, a temporary assignment of NAD '83 HARN or HPGN may better approximate local conditions. Plain NAD '83 was used for the primary deliverable in order to avoid any implication of higher precision; however, the user may want to evaluate other approximations for specific applications. At such time as ESRI includes support for NAD '83 CORS '96, the temporary NAD '83 assignment in the .prj file should be replaced with NAD '83 CORS '96 without further reprojection.

The NOAA Office for Coastal Management has converted the data to ellipsoid heights (using Geoid09) and NAD 83 geographic coordinates for data storage and Digital Coast provisioning purposes.

In addition to these lidar point data, the bare earth Digital Elevation Models (DEM) created from the lidar point data, and the breaklines are also available. These data are available for custom download at the links provided in the URL section of this metadata record.

Original contact information:

Contact Name: Jacob MacDonald

Contact Org: US Army Corps of Engineers, Portland District

Phone: 503-808-4844

Email: jacob.macdonald@usace.army.mil

Provide high resolution terrain elevation and land cover elevation data for the purpose of supporting hydraulic modeling related to the Columbia River Treaty Project.

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The following layer name attributes were assigned to digitized breakline features. All features were digitized as 3D breaklines.

BREAKLINE - Added to the ground model for features not recognized as ground by the LiDAR ground classification model. Typically includes cliffs

and similar hard breaks. Digitized from first return surface.

BREAKLINE_OBSCURE - Interpolated breaklines in vegetated areas with minimal ground penetration; used only for significant/readily identifiable

features that could be reasonably interpolated from available ground points and adjacent visible ground. These lines are interpreted from

visible data and fit to visible ground data.

WATER_MAIN - Main rivers, not including side rivers and streams. Designed to be the river in the center of the coverage area, Columbia, Snake, etc.

WATER_OTHER - Covers side rivers, lakes, ponds etc. This coverage is not intended to capture all water outside the main rivers but only water edges

that need a breakline and need LiDAR data re-classified. Typically, this includes streams down to approximately 2 meters in width. No single line

streams are collected.

WATER_ISLAND - Islands in the rivers and streams.

Ground point LAS file classifications:

1 -- Default/not classified

2 -- Bare earth / ground, regular point (not key point)

8 -- Bare earth / ground, model key point

9 -- Water: bare earth / ground, inside water polygon

Not provided

Any conclusions drawn from the analysis of this information are not the responsibility of the US Army Corps of Engineers (USACE), the Office for Coastal Management or its partners.

Data is available online for custom and bulk downloads.

None

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.

Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.0.1770

Processes were designed to achieve a horizontal accuracy for unobscured raw point cloud data of less than 30 cm.

See LiDAR data report at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1122/supplemental/ColumbiaRiverLiDARProject_FinalSummaryReport.doc

Processes were designed to meet a scope of work vertical accuracy requirement of 13 cm Root Mean Square Error (RMSE) for the final integrated

ground model. Vegetated areas could not be assessed using softcopy photogrammetry methods and may not meet this accuracy in all cases.

Open, hard pavement areas significantly exceed this requirement. The RMSE of the data for open, hard-packed surfaces is 0.046 meters as

assessed from 40,266 ground survey (real time kinematic) points taken on hard-packed road surfaces.

See LiDAR data report at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1122/supplemental/ColumbiaRiverLiDARProject_FinalSummaryReport.doc

; Quantitative Value: 0.046 meters, Test that produced the value:

The RMSE of the data for open, hard-packed surfaces is 0.046 meters as assessed from 40,266 ground survey (real time kinematic) points taken

on hard-packed road surfaces. This value is representative of anticipated accuracies in open, evenly sloped or flat terrain where maximum point

densities were achieved. To assess accuracies in other terrain conditions, a detailed photogrammetric review using LiDAR stereograms was conducted.

The review was focused on significant and readily identifiable features of 0.5 m height or larger. Areas where the initial ground model point

densities did not appear to support the 13 cm RMSE target accuracy were identified and corrected with supplemental breaklines to create an

integrated terrain model designed to meet accuracy requirements.

LiDAR data has been collected and processed for all areas within the project study area.

LiDAR flight lines have been examined to ensure that there was at least 60% sidelap; there are no gaps between flightlines, and overlapping

flightlines have consistent elevation values.

Professional surveyor oversight was implemented for the base station control survey. All control point data was reviewed by a professional surveyor,

processed for and NGS OPUS DB solution and for inclusion in the database. 10% of the field points were verified by an independent GPS survey quality

control check. All new monuments were submitted for publication on the OPUS online datasheet website.

Ground point classifications were reviewed in detail both by visual review during the initial LiDAR processing and again during a photogrammetric

review against stereograms generated from first return LiDAR intensities.

Shaded relief images have been visually inspected for data errors such as pits, border artifacts, gaps, and shifting. The data was examined at

a 1:2000 scale.

An overall review including mosaicing all imagery and developing a geodatabase of all .las files, raster and vector deliverables was performed

as a final quality control check.