kingcounty_delivery4_block2_be

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: Quantum Spatial

Publication_Date: 20170622

Title: kingcounty_delivery4_block2_be

Geospatial_Data_Presentation_Form: raster digital data

Description:

Abstract:

The bare earth digital elevation model (DEM) represents the earth's surface with all vegetation and human-made structures removed. It is derived from NIR LiDAR data using TIN processing of the ground point returns. Some elevation values have been interpolated across areas in the ground model where there is no elevation data (e.g. over water, under dense vegetation). Data was processed in reference to NAD83 (CORS96), however the horizontal datum for this dataset is defined as NAD83 (HARN) as the difference is generally small and allows for greater ease of use with data in different datums. The vertical datum is NAVD88, Geoid 03, and the data is projected in Washington State Plane North. Units are in US Survey Feet. Quantum Spatial collected the PSLC King County LiDAR Delivery 4 - Block 2 LiDAR data for the Puget Sound LiDAR Consortium between 03/17/16 and 05/25/17.

Purpose:

Provide high resolution terrain elevation data from the PSLC King County LiDAR Delivery 4 - Block 2 LiDAR dataset.

Supplemental_Information:

This data is assembled by 1/4th USGS Quadrangles and projected in Washington State Plane North.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 20160317

Ending_Date: 20170525

Currentness_Reference: PSLC King County LiDAR

Status:

Progress: Complete

Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -121.946279

East_Bounding_Coordinate: -121.394496

North_Bounding_Coordinate: 47.608208

South_Bounding_Coordinate: 47.166571

Keywords:

Theme:

Theme_Keyword_Thesaurus: None

Theme_Keyword:

LiDAR, Light Detection and Ranging, high-resolution, elevation data, topography, bare earth, DEM, digital elevation model

Theme:

Theme_Keyword_Thesaurus: ISO 19115 Topic Categories

Theme_Keyword: elevation

Place:

Place_Keyword_Thesaurus: None

Place_Keyword: King County

Place_Keyword: Washington

Access_Constraints: None

Use_Constraints:

In some areas of heavy vegetation or forest cover, there may be relatively few ground points in the LiDAR data. TINing the points produces large triangles and hence the elevations may be less accurate within such areas. Elevation values for open water surfaces should be considered approximate due to the increase of laser noise seen over water, frequent lack of returns, and the overall dynamic nature of water.

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Puget Sound LiDAR Consortium

Contact_Person: Andy Norton

Contact_Address:

Address_Type: mailing

Address: 1011 Western Avenue, Suite 500

City: Seattle

State_or_Province: Washington

Postal_Code: 98104

Country: US

Contact_Voice_Telephone: 206-971-3283

Contact_Electronic_Mail_Address: anorton@psrc.org

Data_Set_Credit: Puget Sound LiDAR Consortium

Native_Data_Set_Environment: Version 6.2 (Build 9200) ; Esri ArcGIS 10.4.1.5686

Data_Quality_Information:

Logical_Consistency_Report:

Shaded relief images have been visually inspected for data errors such as pits, border artifacts, and shifting. LiDAR flight lines have been examined to ensure consistent elevation values across overlapping flight lines. The Root Mean Square Error (RMSE) of line to line relative accuracy for this dataset is 0.209 ft (0.064 m). Please see the LiDAR data report for a discussion of the statistics related to this dataset.

Completeness_Report:

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

Positional_Accuracy:

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

The Non-Vegetated Vertical Accuracy (NVA) of this dataset, tested at 95% confidence level is 0.174 ft (0.053 m). Please see the LiDAR data report for a discussion of the statistics related to this dataset.

Quantitative_Vertical_Positional_Accuracy_Assessment:

Vertical_Positional_Accuracy_Value: 0.174 ft (0.053 m)

Vertical_Positional_Accuracy_Explanation:

Non-Vegetated Vertical Accuracy was assessed using 53 ground check points. These check points were not used in the calibration or post processing of the LiDAR point cloud data.

Lineage:

Process_Step:

Process_Description:

Acquisition. Quantum Spatial collected the PSLC King County LiDAR Delivery 4 - Block 2 LiDAR data between 03/17/16 and 05/25/17. The survey used a Leica ALS80 laser system mounted in a Cessna Caravan 208B. Data was collected using a multi pulse flight plan. Ground level GPS and aircraft IMU were collected during the flight.
Sensor: Leica ALS80 (03/17/2016, 03/26/2016, 03/29/2016, 08/19/2016, 08/20/2016, 08/24/2016 – 08/26/2016, 08/28/2016, 04/21/2017, 05/09/2017, 05/25/2017): Maximum returns: unlimited Nominal pulse density: 8 ppsm pulses/m^2 Nominal pulse spacing: .35 m AGL: 1600 m Speed: 145 knots FOV: 30° Scan frequency: 53.0 hz Pulse rate: 340 kHz Pulse duration: 2.5 ns Pulse width: 35.0 cm Wavelength: 1064 nm Pulses in air mode: Multiple Pulses in Air Beam divergence: 22 mrads Swath width: 857 m Overlap: 63%

Process_Date: 20170525

Process_Step:

Process_Description:

1. Flight lines and data were reviewed to ensure complete coverage of the study area and positional accuracy of the laser points. 2. Laser point return coordinates were computed using Waypoint Inertial Explorer and Leica Cloudpro software based on independent data from the LiDAR system, IMU, and aircraft. 3. The raw LiDAR file was assembled into flight lines per return with each point having an associated x, y, and z coordinate. 4. Visual inspection of swath to swath laser point consistencies within the study area were used to perform manual refinements of system alignment. 5. Custom algorithms were designed to evaluate points between adjacent flight lines. Automated system alignment was computed based upon randomly selected swath to swath accuracy measurements that consider elevation, slope, and intensities. Specifically, refinement in the combination of system pitch, roll and yaw offset parameters optimize internal consistency. 6. Noise (e.g., pits and birds) was filtered using postprocessing software, based on known elevation ranges and included the removal of any cycle slips. 7. Using TerraScan and Microstation, ground classifications utilized custom settings appropriate to the study area. 8. The corrected and filtered return points were compared to the ground survey points collected to verify the vertical accuracy. 9. TIN processing of the ground point returns was used to create this bare earth DEM.

Process_Date: 20170525

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Raster

Raster_Object_Information:

Raster_Object_Type: Grid Cell

Row_Count: 7644

Column_Count: 4566

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Map_Projection:

Map_Projection_Name: NAD 1983 HARN StatePlane Washington North FIPS 4601 Feet

Lambert_Conformal_Conic:

Standard_Parallel: 47.5

Standard_Parallel: 48.73333333333333

Longitude_of_Central_Meridian: -120.8333333333333

Latitude_of_Projection_Origin: 47.0

False_Easting: 1640416.666666667

False_Northing: 0.0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: coordinate pair

Coordinate_Representation:

Abscissa_Resolution: 0.000000026366619998441372

Ordinate_Resolution: 0.000000026366619998441372

Planar_Distance_Units: foot_us

Geodetic_Model:

Horizontal_Datum_Name: D North American 1983 HARN

Ellipsoid_Name: GRS 1980

Semi-major_Axis: 6378137.0

Denominator_of_Flattening_Ratio: 298.257222101

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Puget Sound LiDAR Consortium

Contact_Person: Andy Norton

Contact_Address:

Address_Type: mailing

Address: 1011 Western Avenue, Suite 500

City: Seattle

State_or_Province: Washington

Postal_Code: 98104

Country: US

Contact_Voice_Telephone: 206-971-3283

Contact_Electronic_Mail_Address: anorton@psrc.org

Distribution_Liability:

Please contact the Puget Sound LiDAR Consortium for information regarding the use of this data.

Metadata_Reference_Information:

Metadata_Date: 20170818

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Quantum Spatial

Contact_Address:

Address_Type: mailing and physical

Address: 517 SW 2nd St., Suite 400

City: Corvallis

State_or_Province: OR

Postal_Code: 97333

Country: US

Contact_Voice_Telephone: 541-752-1204

Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Time_Convention: local time