Thurston County LiDAR, Hydro-enforced DEM

Metadata also available as

Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: Thurston Geodata Center
Publication_Date: 20120314
Title: Thurston County LiDAR, Hydro-enforced DEM
Edition: v.01
Geospatial_Data_Presentation_Form: map
Series_Information:
Series_Name: LiDAR
Issue_Identification: 1
Publication_Information:
Publication_Place: Olympia, WA
Publisher: Thurston Geodata Center
Online_Linkage: <https://www.geodata.org/ordering.htm>
Description:
Abstract:
Light Detection and Ranging (LiDAR) data is remotely sensed high-resolution elevation data collected by an airborne collection platform. This LiDAR dataset is a survey of Thurston County and 20 square miles of Gray's Harbor county encompassing land within the jurisdiction of the Confederated Chehalis Tribe. The project area consists of approximately 825 square miles. The project design of the LiDAR data acquisition was developed to support a nominal post spacing of 1 meter. Fugro EarthData, Inc. acquired 283 flight lines in 15 lifts between June 2011 and July 2011. LiDAR data collection was performed with a Cessna 310 twin engine aircraft, utilizing a Leica ALS60 MPiA sensor; collecting multiple return x, y, and z as well as intensity data.
Purpose:
The Purpose of the Thurston GeoData Center is to provide County staff with accurate spatial geographic information and provide access and support in utilizing this information in their daily operations. Secondarily, the Thurston GeoData Center provides support and services to Federal, State, and local agencies, private business and the general public.These digital data are intended to support entities in their decision-making processes.
Supplemental_Information:
The information in this report is the result of LiDAR surveys performed on the date indicated and the general conditions at the time of flight.
Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 20110702
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -123.287441
East_Bounding_Coordinate: -122.191247
North_Bounding_Coordinate: +47.213223
South_Bounding_Coordinate: +46.741667
Keywords:
Theme:
Theme_Keyword_Thesaurus: Keywords
Theme_Keyword: LiDAR
Theme_Keyword: Bare Earth
Theme_Keyword: Terrain
Theme_Keyword: Model
Theme_Keyword: Elevation
Theme_Keyword: Surface
Place:
Place_Keyword_Thesaurus: Geographic Names Information System
Place_Keyword: US
Place_Keyword: Thurston County
Place_Keyword: Gray's Harbor County
Place_Keyword: Washington
Access_Constraints: NONE
Use_Constraints:
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.
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Thurston Geodata Center
Contact_Address:
Address_Type: mailing and physical address
Address: 929 Lakeridge Drive SW
City: Olympia
State_or_Province: Washington
Postal_Code: 98502
Country: USA
Address: Suite 216
Contact_Voice_Telephone: 360-754-4594
Contact_Electronic_Mail_Address: maps@geodata.org
Hours_of_Service: 9:00am - 5:00pm
Data_Set_Credit: Thurston Geodata Center
Security_Information:
Security_Classification_System: None
Security_Classification: Unclassified
Security_Handling_Description: N/A
Native_Data_Set_Environment:
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.6.1500
Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
During LiDAR data collection the airborne GPS receiver was collecting data at 2 Hz frequency and the Dilution of Precision (PDOP) was monitored. One GPS base station was also running at the operation airport and was recording data at 1 Hz. The airborne GPS data was post-processed in DGPS mode together with the base station data to provide high accuracy aircraft positions. The GPS trajectory then was combined with the IMU data using loosely coupled approach to yield high accuracy aircraft positions and attitude angles. Then the LiDAR data was processed using the aircraft trajectory and raw LiDAR data. After boresighting the LiDAR data, the ground control points were measured against the LiDAR data by technicians using TerraScan and proprietary software and the LiDAR data was adjusted vertically to the ground control. Independent ground control check points were used to ensure vertical accuracy of the data. The horizontal datum for the control was the North American Datum of 1983 (NAD83, NSRS2007).The vertical datum was the North American Vertical Datum of 1988 (NAVD88). The vertical datum was realized through the use of the published/calculated ellipsoidal heights of the base station to process the aircraft trajectory and then later applying the GEOID09 model to the processed LiDAR data to obtain orthometric heights.
Logical_Consistency_Report:
Compliance with the accuracy standard was ensured by the collection of ground control and the establishment of a GPS base station at the operation airport. The following checks were performed: 1) The LiDAR data accuracy was validated by performing a full boresight adjustment and then checking it against the ground control prior to generating a digital terrain model (DTM) or other products. 2) LiDAR elevation data was validated through an inspection of edge matching and visual inspection for quality (artifact removal).
Completeness_Report:
The following methods are used to ensure LiDAR data accuracy: 1) Use of a ground control network utilizing GPS survey techniques; 2) Use of airborne GPS and IMU in conjunction with the acquisition of LiDAR; and 3) Measurement of quality control ground survey points within the finished product. The following software is used for the validation: 1) Terrascan and 2) Fugro EarthData Proprietary Software.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
When compared to GPS survey grade points in generally flat non-vegetated areas, at least 95% of the positions shall have an error less than or equal to 18.2 cm (equivalent to root mean square error of 9.25 cm if errors were normally distributed).
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
The consolidated vertical accuracy of vertical checkpoints (z-values) consolidated for two or more of the major land cover categories, representing both open terrain and other land cover categories.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: Fugro EarthData, Inc.
Publication_Date: 20111215
Title: Aerial Acquisition of Thurston County LiDAR
Type_of_Source_Media: External hard drive
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20110604
Ending_Date: 20110702
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: Aerial LiDAR Acquisition
Source_Contribution:
Fugro EarthData, Inc. acquired 283 flight lines in 15 lifts between June 2011 and July 2011. LiDAR data collection was performed with a Cessna 310 twin engine aircraft, utilizing a Leica ALS60 MPiA sensor acquiring a nominal post spacing of 1 meter. The lines were flown at altitudes between 5900 and 7225 feet above mean terrain using pulse rates of 107,500 to 126,200 pulses per second. The collection was performed using Leica ALS60 MPiA LiDAR systems, serial number 142.
Source_Information:
Source_Citation:
Citation_Information:
Originator: TerraSurv
Publication_Date: 20110701
Title: Report of LiDAR Control Survey - Thurston County, Washington
Type_of_Source_Media: electronic mail system
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 2011523
Ending_Date: 20110604
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: Ground Control
Source_Contribution:
TerraSurv under contract to Fugro EarthData, Inc. successfully established ground control for this project. A total of 53 ground control points were acquired. GPS was used to establish the control network. The horizontal datum was the North American Datum of 1983 (NAD83, NSRS2007). The vertical datum was the North American Vertical Datum of 1988 (NAVD88).
Source_Information:
Source_Citation:
Citation_Information:
Originator: Fugro EarthData, Inc.
Publication_Date: 20111020
Title: Thurston County LiDAR; Classified LiDAR Point Cloud Data
Type_of_Source_Media: Internal network
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 20111020
Source_Currentness_Reference: Publication Date
Source_Citation_Abbreviation: Classified LiDAR Point Cloud Data
Source_Contribution:
Fugro EarthData, Inc. utilized commercial software as well as proprietary software for automatic filtering. The parameters used in the process were customized for each terrain type to obtain optimum results. Once the automated filtering was completed, the files were run through a visual inspection to ensure that the filtering was not too aggressive or not aggressive enough. In cases where the filtering was too aggressive and important terrain features were filtered out, the data was either run through a different filter or was corrected during the manual filtering process. Interactive editing was then completed in 3D visualization software which also provides manual and automatic point classification tools using commercial and proprietary software for the process. Vegetation and artifacts remaining after automatic data post-processing were reclassified manually through interactive editing. The hard edges of ground features that were automatically filtered out during the automatic filtering process were brought back into ground class during manual editing. The technician then reviewed the LiDAR points with color shaded TINs for anomalies in ground class during interactive filtering. Upon the completion of bare earth filtering and peer review process, the classified LiDAR point cloud work tiles were ready for the collection of hydro breaklines.
Process_Step:
Process_Description:
The hydro-enforced bare earth DEM was generated using the bare earth points, as well as the 3D hydro breaklines. The following is a step-by-step breakdown of the process: 1) After the deliverable LAS files were generated for the entire project area and QC'ed, and the 3D breaklines were collected and QC'ed, they were used to produce the hydro-enforced bare earth DEM. The bare earth points that fell within 1*NPS along the hydro breaklines were taken out of from Ground class so that these points were excluded from the DEM generation process. This process was done in batch mode using Fugro EarthData's proprietary software. 2) Inland ponds and lakes, inland streams and rivers, and tidal water bodies were hydro-flattened within the DEM. Hydro-flattening was applied to water impoundments, natural or man-made, larger than ~0.5 acres in area; to streams nominally wider than 25'; and to tidal waters bodies, which includes any significant water body that is affected by tidal variations. 3) The hydro-flattened bare earth DEM generated in initial grid format was then clipped to the approved DEM product boundary. 4) After the hydro-flattened bare earth DEM was clipped to the boundary, the technician checked the tiles to ensure that the grid spacing met specifications and checked the surface to ensure proper hydro-flattening. The data was cut to the approved tile layout. The entire data set was checked for complete project coverage and to ensure it was free of anomalies. 5) The hydro-flattened bare earth DEM was then converted to the delivery ESRI Grid format.
Source_Used_Citation_Abbreviation: Classified LiDAR Point Cloud Data
Process_Date: 20111115
Source_Produced_Citation_Abbreviation: Hydro-Flattened Bare Earth DEM
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Fugro EarthData, Inc.
Contact_Person: Rich McClellan
Contact_Position: Project Manager
Contact_Address:
Address_Type: mailing and physical address
Address: 7320 Executive Way
City: Frederick
State_or_Province: MD
Postal_Code: 21704
Country: USA
Contact_Voice_Telephone: 301.948.8550
Contact_Facsimile_Telephone: 301.963.2064
Contact_Electronic_Mail_Address: rmcclellan@fugro.com
Hours_of_Service: Mon-Fri 8:30am to 5:00pm
Cloud_Cover: 0
Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Point
Point_and_Vector_Object_Information:
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: Point
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:
Abscissa_Resolution: 1
Ordinate_Resolution: 1
Planar_Distance_Units: survey feet
Map_Projection:
Map_Projection_Name: Lambert Conformal Conic
Lambert_Conformal_Conic:
Standard_Parallel: 45.833333
Standard_Parallel: 47.333333
Longitude_of_Central_Meridian: -120.500000
Latitude_of_Projection_Origin: 45.333333
False_Easting: 1640416.666667
False_Northing: 0
Geodetic_Model:
Horizontal_Datum_Name:
North American Datum of 1983 (National Spatial Reference System 2007)
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137.000000
Denominator_of_Flattening_Ratio: 298.257222
Vertical_Coordinate_System_Definition:
Altitude_System_Definition:
Altitude_Datum_Name: North American Vertical Datum of 1988
Altitude_Resolution: 1
Altitude_Distance_Units: Feet
Altitude_Encoding_Method:
Explicit elevation coordinate included with horizontal coordinates
Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview: Leica ALS60 MPiA sensor; 1m nominal post spacing
Entity_and_Attribute_Detail_Citation: see process steps within this record
Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Thurston Geodata Center
Contact_Address:
Address_Type: mailing and physical address
Address: 929 Lakeridge Drive SW
City: Olympia
State_or_Province: Washington
Postal_Code: 98502
Country: USA
Address: Suite 216
Contact_Voice_Telephone: 360-754-4594
Contact_Electronic_Mail_Address: maps@geodata.org
Hours_of_Service: 9:00am - 5:00pm
Resource_Description: Downloadable Data
Distribution_Liability:
Any conclusions drawn from the analysis of this information are not the responsibility of Thurston Geodata Center
Custom_Order_Process:
//www.csc.noaa.gov/ldart. This data set is dynamically generated based on user-specified parameters.
Metadata_Reference_Information:
Metadata_Date: 20120314
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Thurston Geodata Center
Contact_Address:
Address_Type: mailing and physical address
Address: 929 Lakeridge Drive SW
City: Olympia
State_or_Province: Washington
Postal_Code: 98502
Country: USA
Address: Suite 216
Contact_Voice_Telephone: 360-754-4594
Contact_Electronic_Mail_Address: maps@geodata.org
Hours_of_Service: 9:00am - 5:00pm
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Access_Constraints: None
Metadata_Use_Constraints: None
Generated by mp version 2.9.12 on Wed Nov 20 07:27:40 2013