2002 NASA/USGS Airborne LiDAR Assessment of Coastal Erosion (ALACE) Project for California, Oregon, and Washington Coastlines

Metadata:

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

Identification_Information:

Citation:

Citation_Information:

Originator:

Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), Coastal Services Center (CSC)

Publication_Date: Unknown

Title:

2002 NASA/USGS Airborne LiDAR Assessment of Coastal Erosion (ALACE) Project for California, Oregon, and Washington Coastlines

Publication_Information:

Publication_Place: Charleston, SC

Publisher: NOAA's Ocean Service, Coastal Services Center (CSC)

Online_Linkage: <http://www.csc.noaa.gov/ldart>

Description:

Abstract:

Laser beach mapping uses a pulsed laser ranging system mounted onboard an aircraft to measure ground elevation and coastal topography. The laser emits laser beams at high frequency and is directed downward at the earth's surface through a port opening in the bottom of the aircraft's fuselage. The laser system records the time difference between emission of the laser beam and the reception of the reflected laser signal in the aircraft. The aircraft travels over the beach at approximately 60 meters per second while surveying from the low water line to the landward base of the sand dunes.

Purpose:

This data was collected as part of an effort by the USGS and NASA to map beach topography and assess beach change for the states of California, Oregon and Washington.

Supplemental_Information:

This data set was collected with the NASA Airborne Topographic Lidar 3 (ATM3) LIDAR (LIght Detection and Ranging) instrument which was designed and developed by the NASA Observational Science Branch (OSB Code 972) Goddard Space Flight Center, Wallops Island VA. The ATM3 measures the time of flight of a narrow pulse (5 nanoseconds) of green laser light (532 nm) from the aircraft to the ground and back to the aircraft. The laser is pulsed at 5000 Hz and the pulses are reflected from a 22 degree off-nadir scanning mirror rotating at 20 Hz which directs the laser light and the telescope view in an elliptical scan pattern under the aircraft. The telescope collects the reflected laser light which passes through a narrow bandpass filter (to reject background light) and is detected by a photomultiplier tube detector. The ATM3 time of flight measurements are calibrated and combined with GPS data (to provide position) and aircraft inertial gyro data (to provide the aircraft attitude when each laser measurement was recorded) resulting in a calculated latitude, longitude, and elevation for each laser spot in the 250 laser shot elliptical scan under the aircraft. The scan pattern (at 22 degrees off nadir) covers a width of ~ 560 meters from a nominal aircraft altitude of 700 meters. Depending on aircraft ground speed, several consecutive scans may overlap along the aircraft flight track. Normally parallel flight tracks will be flown with ~20% overlap to cover areas wider than a single ATM3 scan width. The resultant data set is normally resampled and binned to create a digital elevation model of the desired area. Note: The Spatial Reference section of this document may lack fully FGDC-compliant information regarding projection parameters (i.e., Central meridian, false Northing, etc.). The State Plane or UTM Zone will be supplied, and the corresponding parameters can be found in Appendix C of: Snyder, John, 1987, Map Projections, a Working Manual (U.S. Geological Survey Professional Paper 1395): Washington, U.S. Government Printing Office.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 20020918

Ending_Date: 20021003

Currentness_Reference: Ground condition

Status:

Progress: Complete

Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -128.111

East_Bounding_Coordinate: -119.611

North_Bounding_Coordinate: 48.389465

South_Bounding_Coordinate: 36.933602

Keywords:

Theme:

Theme_Keyword_Thesaurus: ISO 19115 Topic Category

Theme_Keyword: Elevation

Theme:

Theme_Keyword_Thesaurus: None

Theme_Keyword: lidar

Theme_Keyword: laser

Theme_Keyword: beach

Theme_Keyword: Bathymetry/Topography

Theme_Keyword: digital elevation model

Theme_Keyword: DEM

Theme_Keyword: erosion

Place:

Place_Keyword_Thesaurus: None

Place_Keyword: US West Coast

Place_Keyword: California

Place_Keyword: Oregon

Place_Keyword: Washington

Access_Constraints: None

Use_Constraints:

This data was collected for the purposes of research. Any conclusions drawn from analysis of this information are not the responsibility of NASA, USGS, or NOAA. This data is likely to contain returns from the water surface and vegetation. No processing has been done to remove returns from water or vegetation. 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:

Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS). Coastal Services Center (CSC)

Contact_Position: CEM Project Scientist

Contact_Address:

Address_Type: mailing and physical address

Address: 2234 South Hobson Avenue

City: Charleston

State_or_Province: South Carolina

Postal_Code: 29405

Country: United States

Contact_Voice_Telephone: (843) 740-1200

Contact_Electronic_Mail_Address: tcm@csc.noaa.gov

Data_Set_Credit:

This Airborne Topographic Mapper LIDAR data set was collected in partnership with the NASA Wallops Flight Facility, and the U. S. Geological Survey (USGS) Center for Coastal and Regional Marine Geology.

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

See Vertical_Positional_Accuracy_Report. Processing steps (datum conversion, projection, grid interpolation, etc.) introduce additional error factors which have not been tested at the time of this publication.

Logical_Consistency_Report: Not applicable.

Completeness_Report: None

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

The ATM LIDAR elevation points are estimated to be horizontally accurate to +/- 0.8 meters at an aircraft altitude of 700 meters.

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

The accuracy of this data set has not been validated against ground truth measurements. An internal consistency check of the data was conducted. The process compared elevation points determined to be over beaches and non-vegetated areas from overlapping flights. The elevation of points within a meter of each other were compared. The average RSME of the 60 sample areas each containing on average 1311 common points was 18.5 cm. In comparisons of another ATM LIDAR data set for a small geographic region to various ground surveys the differences are between +/- 15 to 20 centimeters. The accuracy of the majority of this data set is estimated to be consistent with the above stated results.

Lineage:

Process_Step:

Process_Description:

The xyz coordinates of this data set were transformed from ITRF_2000 to ITRF_1994 using datum transformation parameters from the National Geodetic Survey’s HTDP software.

Process_Date: 20040801

Process_Step:

Process_Description:

The vertical values in this data set have been filtered through visual inspection to find abnormally high and abnormally low values. In addition, these data have been filtered using a spatial filtering program that identifies and discards outlier elevation measurements. This program reads each elevation measurement within a file and identifies "spatially close" points (i.e. those neighboring points within a fixed radius of the point). The mean and standard deviation is calculated using the elevations of these points. If the elevation difference from the mean of the point under consideration is more than 2 standard deviations and greater than a defined distance the point is discarded.

Process_Date: Unknown

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:

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:

Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), Coastal Services Center (CSC)

Contact_Position: CEM Project Scientist

Contact_Address:

Address_Type: mailing and physical address

Address: 2234 South Hobson Avenue

City: Charleston

State_or_Province: SC

Postal_Code: 29405-2413

Contact_Voice_Telephone: 843-740-1200

Contact_Electronic_Mail_Address: tcm@csc.noaa.gov

Resource_Description: Downloadable Data

Distribution_Liability:

This data was collected for the purposes of research. Any conclusions drawn from analysis of this information are not the responsibility of NOAA, the Coastal Services Center or its partners.

Custom_Order_Process:

This data can be obtained on-line at the following URL: <http://www.csc.noaa.gov/ldart>. The data set is dynamically generated based on user-specified parameters.

Metadata_Reference_Information:

Metadata_Date: 20021210

Metadata_Review_Date: 20070625

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:

Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), Coastal Services Center (CSC)

Contact_Position: CEM Project Scientist

Contact_Address:

Address_Type: mailing and physical address

Address: 2234 South Hobson Avenue

City: Charleston

State_or_Province: SC

Postal_Code: 29405-2413

Contact_Voice_Telephone: 843-740-1200

Contact_Electronic_Mail_Address: tcm@csc.noaa.gov

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998