Identification_Information: Citation: Citation_Information: Originator: Adam R. Mosbrucker Publication_Date: 2014 Title: High-resolution digital elevation model of Mount St. Helens crater and upper North Fork Toutle River basin, Washington, based on an airborne lidar survey of September 2009 Geospatial_Data_Presentation_Form: raster digital data Series_Information: Series_Name: Data Series Issue_Identification: DS 904 Publication_Information: Publication_Place: Reston, Virginia Publisher: U.S. Geological Survey Online_Linkage: http://dx.doi.org/10.3133/ds904 Description: Abstract: The lateral blast, debris avalanche, and lahars of the May 18th, 1980, eruption of Mount St. Helens, Washington, dramatically altered the surrounding landscape. Lava domes were extruded during the subsequent eruptive periods of 1980-1986 and 2004-2008. More than three decades after the emplacement of the 1980 debris avalanche, high sediment production persists in the North Fork Toutle River basin, which drains the northern flank of the volcano. Because this sediment increases the risk of flooding to downstream communities on the Toutle and Cowlitz Rivers, the U.S. Army Corps of Engineers (USACE), under the direction of Congress to maintain an authorized level of flood protection, built a sediment retention structure on the North Fork Toutle River in 1989 to help reduce this risk and to prevent sediment from clogging the shipping channel of the Columbia River. From September 16-20, 2009, Watershed Sciences, Inc., under contract to USACE, collected high-precision airborne lidar (light detection and ranging) data that cover 214 square kilometers (83 square miles) of Mount St. Helens and the upper North Fork Toutle River basin from the sediment retention structure to the volcano's crater. These data provide a digital dataset of the ground surface, including beneath forest cover. Such remotely sensed data can be used to develop sediment budgets and models of sediment erosion, transport, and deposition. The U.S. Geological Survey (USGS) used these lidar data to develop digital elevation models (DEMs) of the study area. DEMs are fundamental to monitoring natural hazards and studying volcanic landforms, fluvial and glacial geomorphology, and surface geology. Watershed Sciences, Inc., provided files in the LASer (LAS) format containing laser returns that had been filtered, classified, and georeferenced. The USGS produced a hydro-flattened DEM from ground-classified points at Castle, Coldwater, and Spirit Lakes. Final results averaged about five laser last-return points per square meter. As reported by Watershed Sciences, Inc., vertical accuracy is 10 centimeters (cm) at the 95-percent confidence interval on bare road surfaces; however, over natural terrain, USGS found vertical accuracy to be 10-50 cm. This USGS data series contains the bare-earth lidar data as 1- and 10-meter (m) resolution Esri grid files. Digital-elevation data can be downloaded (1m_DEM.zip and 10m_DEM.zip), as well as a 1-m resolution hillshade image with pyramids (1m_hillshade.zip). These geospatial data files require geographic information system (GIS) software for viewing. Purpose: This dataset provides high-resolution digital elevation data of the Mount St. Helens crater and upper North Fork Toutle River basin. Data are used for a wide variety of natural-hazard monitoring and assessment activities and the study of geomorphology and geology in the basin. Supplemental_Information: Point density in more than 86 percent of raster extent is high enough to support 1.0-m resolution grid cell size. Nearly 14 percent of the raster extent does not support this resolution. Because of limited laser returns at the ground level in dense vegetation, a greater degree of interpolation is required to generate a surface model. This results in a greater degree of uncertainty in these areas. Time_Period_of_Content: Time_Period_Information: Multiple_Dates/Times: Single_Date/Time: Beginning_Date: September 16, 2009 Single_Date/Time: Ending_Date: September 20, 2009 Currentness_Reference: publication date Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -122.575804 East_Bounding_Coordinate: -122.095600 North_Bounding_Coordinate: 46.377553 South_Bounding_Coordinate: 46.190141 Keywords: Theme: Theme_Keyword_Thesaurus: none Theme_Keyword: Mount St. Helens Theme_Keyword: lidar Theme_Keyword: topography Theme_Keyword: elevation Theme_Keyword: North Fork Toutle River Theme_Keyword: volcanic landforms Place: Place_Keyword_Thesaurus: none Place_Keyword: Mount St. Helens Place_Keyword: Cascade Range Place_Keyword: Washington Place_Keyword: USA Access_Constraints: None Use_Constraints: Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The USGS shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Adam R. Mosbrucker Contact_Organization: U.S. Geological Survey Contact_Position: Hydrologic Technician Contact_Address: Address_Type: mailing address Address: 1300 SE Cardinal Court, Building 10, Suite 100 City: Vancouver State_or_Province: WA Postal_Code: 98683 Country: USA Contact_Voice_Telephone: 360-993-8975 Contact_Electronic_Mail_Address: amosbrucker@usgs.gov?subject=MSH_2009_LiDAR Data_Set_Credit: These data were produced by the USGS from lidar acquired by Watershed Sciences, Inc., under contract to USACE. Watershed Sciences, Inc., provided filtered, classified, and georeferenced point-cloud data in LAS files. The USGS produced hydro-flattened DEMs from ground-classified points. Security_Information: Security_Classification_System: none Security_Classification: Unclassified Security_Handling_Description: none Native_Data_Set_Environment: Microsoft Windows 7 Enterprise Service Pack 1; ESRI ArcGIS 10.0.3.3600 Data_Quality_Information: Logical_Consistency_Report: This is a raster grid file and does not contain topologic relations. Raster file contains NULL values. Completeness_Report: These data completely describe the topographic surface of the surveyed area near Mount St. Helens. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Horizontal positional accuracy has not been determined for these data. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Absolute vertical accuracy is reported as root mean square error (RMSE) and standard deviation by direct comparisons of ground classified points to Real Time Kinematic Global Positioning System (RTK-GPS) survey data on bare road surfaces. RMSE is ±0.035 m and standard deviation is ±0.071 m at the 95-percent confidence interval (2-sigma). Accuracy is likely less on slopes, vegetated areas, and water. Lineage: Process_Step: Process_Description: AIRCRAFT SURVEY--Watershed Sciences, Inc., used Leica lidar ALS50 and ALS60 Phase II lasers mounted in a Cessna Caravan 208B. The Leica systems collect as many as four range measurements per pulse. Opposing flight lines with 50-percent side-lap were flown between 1,300 and 1,400 m above ground level (AGL) over the crater of Mount St. Helens, capturing a scan angle of ±13 degrees and ±12 degrees from nadir, respectively, for an average native density (number of pulses emitted by the lidar system) of greater or equal to eight points per square meter over terrestrial surfaces. Aircraft position (x, y, z) is recorded twice per second (2 hertz, Hz) by an onboard differential GPS unit, and aircraft attitude (pitch, roll, and yaw) is measured 200 times per second (200 Hz) from an onboard inertial measurement unit (IMU) to solve for laser point position. All discernible laser returns were processed for the study area, but some types of surfaces, for example dense vegetation or water, may return fewer pulses than the laser originally emitted, and the final density is spatially variable and has a lower density than the native density. GROUND SURVEY--Before beginning the airborne survey, control monuments were established within 13 nautical miles of all lidar measurement points in the survey area. During the airborne survey, Trimble GPS receivers models R7 and R8 were positioned over either previously established or newly set monuments for static and RTK surveys. The static ground survey location measurements were recorded at a frequency of 1 Hz. Multiple sessions were collected and processed over each monument to confirm antenna height measurements and reported positional accuracy. After the airborne survey, the static GPS data are processed using triangulation with continuous operation stations (CORS) and checked using the Online Positioning User Service (OPUS) to quantify daily variance. The GPS data records are indexed by time and were used to correct the continuous onboard aircraft position measurements recorded throughout the mission. This process provides the location of each laser return relative to that of the static GPS observations. Data accuracy (both relative and absolute) fundamentally depends on the quality of base station observations. DATA PROCESSING--Watershed Sciences, Inc., used commercially available and proprietary software to filter and correct positions, convert to orthometric elevations, classify pulse returns, and produce LAS data files. The USGS used GIS software to generate a bare earth DEM. Processing methods used Esri ArcGIS Desktop (ArcInfo or ArcGIS Advanced version 10 with 3D Analyst and Spatial Analyst extensions). A Python script was authored to automate many geoprocessing steps. The script performed the following functions: (1) create a file geodatabase and feature datasets to manage data, (2) run the Point File Information tool on all LAS files using the native coordinate system and projection, (3) run the LAS to Multipoint tool on all LAS files using the ASPRS (American Society of Photogrammetry and Remote Sensing) class code for ground-classified points and average points spacing from previous step, (4) run the Point to Raster and Map Algebra tools to derive mean intensity, point density, and point spacing raster datasets, (5) ran a number of vector-manipulation tools (slice, conversion, dissolve, eliminate) to generate a data boundary polygon, and (6) create a terrain dataset from nearly 742 million points using a mean window-size pyramid with no thinning. Additional manual processing steps were preformed after the Python script was completed. The data boundary polygon was manually edited using heads-up digitizing at a scale of 1:4,000. Lake surface polygons were manually digitized at a scale of 1:2,000, guided by intensity and point-density rasters, as well as aerial imagery. These polygons were added to the terrain dataset with hard clip and replace functions. Lake elevation at the time of the survey was estimated using edge (lake shore) point elevations. Once the terrain dataset was rebuilt, the Terrain to Raster tool was run using natural neighbors interpolation at a 0-level (all points) pyramid level. This raster was reprojected from NAD83 Washington State Plane South (U.S. survey feet) to NAD83 UTM Zone 10 North (meters). Finally, the Raster Calculator was used to convert elevation units from NAVD88 U.S. survey feet to NAVD88 meters (0.304801 or 3.28083). Process_Date: 2012 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Adam R. Mosbrucker Contact_Position: Hydrologic Technician Contact_Address: Address_Type: Mail Address: 1300 SE Cardinal Court, Building 10, Suite 100 City: Vancouver State_or_Province: WA Postal_Code: 98683 Country: USA Contact_Voice_Telephone: 360-993-8975 Contact_Facsimile_Telephone: 360-993-8980 Contact_Electronic_Mail_Address: amosbrucker@usgs.gov Contact_Instructions: please contact via e-mail Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Pixel Row_Count: 22824 Column_Count: 37168 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: NAD 1983 UTM Zone 10N Transverse Mercator: Longitude_of_Central_Meridian: -123.0 Latitude_of_Projection_Origin: 0.0 False_Easting: 500000.0 False_Northing: 0.0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 0.000000002220024164500956 Ordinate_Resolution: 0.000000002220024164500956 Planar_Distance_Units: meter (1.000000) Geodetic_Model: Horizontal_Datum_Name: D North American 1983 Ellipsoid_Name: GRS 1980 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257222101 Vertical_Datum: Data were converted to orthometric elevations (NAVD88) in meters by applying a GEOID03 correction. Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S Geological Survey Contact_Address: Address_Type: mailing address Address: Box 25286 Address: Denver Federal Center City: Denver State_or_Province: Colorado Postal_Code: 80225-0046 Country: USA Contact_Voice_Telephone: 303-202-4200 Contact_Voice_Telephone: 1-888-ASK-USGS Contact_Facsimile_Telephone: 303-202-4695 Contact_Electronic_Mail_Address: infoservices@usgs.gov Resource_Description: Downloadable data Distribution_Liability: Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The USGS shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: ESRI GRID Raster Format_Version_Date: 20120502 Format_Specification: ESRI GRID Raster File_Decompression_Technique: WinZip Transfer_Size: 604286976 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://pubs.usgs.gov/ds/904/ Fees: free Metadata_Reference_Information: Metadata_Date: 2013 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Adam R. Mosbrucker Contact_Position: Hydrologic Technician Contact_Address: Address_Type: mail Address: 1300 SE Cardinal Court, Building 10, Suite 100 City: Vancouver State_or_Province: WA Postal_Code: 98683 Country: USA Contact_Voice_Telephone: (360) 993-8975 Contact_Facsimile_Telephone: (360) 993-8980 Contact_Electronic_Mail_Address: amosbrucker@usgs.gov Contact_Instructions: please contact via e-mail Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998