2019 OLC Lidar: Portland Metro, OR

Lidar-derived elevation data for the 2019 Oregon Lidar Consortium (OLC) West Metro 3DEP project area. The project area (PA) encompasses 486,551 acres. Data are within Multnomah County, Oregon. The nominal pulse density is eight pulses per square meter. Points that were determined to be geometrically invalid, or invalid surface returns, were removed from the data set. The hydro-flattened bare earth (BE) digital elevation model (DEM) raster grid cell size is 1 meter. The native projection is Albers Equal Area Conic, units are in meters. The native horizontal datum is North American Datum of 1983 (NAD83(2011)); the native vertical datum is North American Vertical Datum of 1988 (NAVD88); (Geoid 12B). Quantum Spatial Inc. collected the lidar and created this dataset in partnership with the Oregon Department of Geology and Mineral Industries (DOGAMI).

Data were subsequently reprocessed to Entwine Point Tile (EPT) format in web mercator projection with vertical meters. The EPT form of the data is used by the NOAA Digital Coast Data Access Viewer, which this metadata record is supporting. Additional processing steps may have been done by the Data Access Viewer and will be recorded in the lineage section.

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.

CONTRACTOR: Quantum Spatial, Inc.

All ground survey data, Lidar data acquisition, calibration, and follow-on processing were completed by the prime contractor, Quantum Spatial, Inc.

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "Exhibit A of Amendment 7 to Price Agreement 7525",

"ldrsens" : "Riegl 1560i",

"ldrmaxnr" : "unlimited",

"ldrnps" : "0.29 m",

"ldrdens" : "12 PPSM",

"ldranps" : "0.29 m",

"ldradens" : "12 PPSM",

"ldrfltht" : "1200 m",

"ldrfltsp" : "105 kts",

"ldrscana" : "58.5 degrees",

"ldrscanr" : "344",

"ldrpulsr" : "2000 kHz",

"ldrpulsd" : "3 ns",

"ldrpulsw" : "0.25 m",

"ldrwavel" : "1064 nm",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25 mrad",

"ldrswatw" : "1348 m",

"ldrswato" : "60%",

"ldrgeoid" : "Geoid 12B"

},

"ldraccur" : {

"ldrchacc" : "0.24",

"rawnva" : "0.077 m",

"rawnvan" : "73"

},

"lasinfo" : {

"lasver" : "1.4",

"lasprf" : "6",

"laswheld" : "Not applicable",

"lasolap" : "Not applicable",

"lasintr" : "16",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Processed, but Unclassified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare-Earth Ground"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "Low Noise"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "In-land Water"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridge Decks"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "High Noise"

},

"lasclass" : {

"clascode" : "20",

"clasitem" : "Ignored Grounds Near Breakline"

}

}}

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. Acknowledgment 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 bulk or custom 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.

LiDAR Mapping Suite 2.4, Applanix PosPac 7.1, Microstation Connect, TerraScan Version 19, TerraModeler Version 19, TerraMatch Version 19, ESRI ArcGIS 10.3.1, Windows 10 Operating System

Contractor Provided:

The project specifications require that only Non-Vegetated Vertical Accuracy (NVA) be computed for raw lidar point cloud swath files. The required accuracy (ACCz) is: 19.6 cm at a 95% confidence level, derived according to NSSDA (i.e., based on RMSE of 10 cm in the "bare earth" and "urban" land cover classes). The Raw Swath NVA was tested with 73 checkpoints located in bare earth and urban (non-vegetated) areas. These checkpoints were not used in the calibration or post processing of the lidar point cloud data. The checkpoints were distributed throughout the project area and were surveyed using GPS techniques. See survey report for additional survey methodologies. Elevations from the unclassified lidar surface were measured for the x,y location of each check point. Elevations interpolated from the lidar surface were then compared to the elevation values of the surveyed control points. AccuracyZ has been tested to meet 19.6 cm or better Non-Vegetated Vertical Accuracy at 95% confidence level using RMSE(z) x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASRPS Guidelines.

The NVA of the raw lidar point cloud swath files was calculated against TINs derived from the final calibrated and controlled swath data using 73 independent checkpoints located in Bare Earth and Urban land cover classes. Tested 0.081 meters NVA at a 95% confidence level using RMSE(z) x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA).

USGS Determined Lidar Point Cloud:

NVA RMSEz (cm) = 3.73

NVA at 95% confidence level (cm) = 7.31

VVA at 95th percentile (cm) = 18.43

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.

Data is backed up to cloud storage.