74010 va2022_stafford_dem_m10232_metadata Data Set Published / External 49404 DEMs - partner (no harvest) Project Completed 2022 2024 Original Dataset Product: These are Digital Elevation Model (DEM) data as part of the required deliverables for the lidar project. Class 2 (Ground) lidar points in conjunction with the hydro breaklines were used to create a 2 foot hydro-flattened Raster DEM. Original Dataset Geographic Extent: Stafford county Virginia, covering approximately 286 square miles. Original Dataset Description: The lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.5 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification 2022, Revision A. The data was developed based on a horizontal projection/datum of NAD83(2011), State Plane Virginia North, Feet and vertical datum of NAVD88 (GEOID18), Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 969 individual 3000 ft x 3000 ft tiles clipped to the DPA, as tiled intensity images, as tiled bare-earth DEMs, as tiled all-return MSHRs; all tiled to the same 3000 ft x 3000 ft schema. Original Dataset Ground Conditions: Lidar was collected in late 2022, while no snow was on the ground and rivers were at or below normal levels. In order to post process the lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines, Sanborn Map Company, Inc., established a total of 4 ground control points that were used to calibrate the lidar to known ground locations established throughout the project area. An additional 14 independent accuracy check points, 9 in Bare Earth and Urban landcovers (9 NVA points), 5 in Tall Grass and Brushland/Low Trees categories (5 VVA points), were used to assess the vertical accuracy of the data. These check points were not used to calibrate or post process the data. This metadata record supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV). For this data set, the DAV is leveraging the USGS GeoTIFF files hosted by USGS on Amazon Web Services. To acquire detailed surface elevation data for use in conservation planning, design, research, floodplain mapping, dam safety assessments and elevation modeling, etc. Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create Intensity Images, Breaklines and Raster DEM. The purpose of these lidar data was to produce high accuracy 3D hydro-flattened Digital Elevation Model (DEM) with a 2 ft cell size. These lidar point cloud data were used to create intensity images, 3D breaklines, hydro-flattened DEMs, and all-return MSHRs as necessary. Raster File Type = TIFF Bit Depth/Pixel Type = 32-bit float Raster Cell Size = 2 feet Interpolation or Resampling Technique = Bilinear Interpolation Required Vertical Accuracy = 19.6 cm NVA Theme Global Change Master Directory (GCMD) Science Keywords EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION Theme Global Change Master Directory (GCMD) Science Keywords EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION > DIGITAL ELEVATION/TERRAIN MODEL (DEM) Theme ISO 19115 Topic Category elevation Spatial Global Change Master Directory (GCMD) Location Keywords CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA Spatial Global Change Master Directory (GCMD) Location Keywords CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > VIRGINIA Spatial Global Change Master Directory (GCMD) Location Keywords VERTICAL LOCATION > LAND SURFACE Instrument Global Change Master Directory (GCMD) Instrument Keywords LIDAR > Light Detection and Ranging Platform Global Change Master Directory (GCMD) Platform Keywords Airplane > Airplane Office for Coastal Management Charleston SC Data Set Elevation None Planned Model (digital) Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners. Acknowledgement of the U.S. Geological Survey would be appreciated for products derived from these data. Data Steward 2024 Organization NOAA Office for Coastal Management NOAA/OCM coastal.info@noaa.gov 2234 South Hobson Ave Charleston SC 29405-2413 (843) 740-1202 https://coast.noaa.gov NOAA Office for Coastal Management Home Page Online Resource Distributor 2024 Organization NOAA Office for Coastal Management NOAA/OCM coastal.info@noaa.gov 2234 South Hobson Ave Charleston SC 29405-2413 (843) 740-1202 https://coast.noaa.gov NOAA Office for Coastal Management Home Page Online Resource Distributor 2024 Organization U.S. Geological Survey 12201 Sunrise Valley Drive Reston VA 20191 USA https://usgs.gov USGS Home Home page for USGS Online Resource Metadata Contact 2024 Organization NOAA Office for Coastal Management NOAA/OCM coastal.info@noaa.gov 2234 South Hobson Ave Charleston SC 29405-2413 (843) 740-1202 https://coast.noaa.gov NOAA Office for Coastal Management Home Page Online Resource Point of Contact 2024 Organization NOAA Office for Coastal Management NOAA/OCM coastal.info@noaa.gov 2234 South Hobson Ave Charleston SC 29405-2413 (843) 740-1202 https://coast.noaa.gov NOAA Office for Coastal Management Home Page Online Resource Ground Condition -77.64 -77.28 38.6 38.23 Discrete 2022-12-13 Discrete 2022-12-20 Discrete 2022-12-27 2 Foot Yes No No No No Vertical EPSG:6360 NAVD88 height (ftUS) North American Vertical Datum 1988 1 Gravity-related height H US survey foot up Projected EPSG:6593 NAD83(2011) / Virginia North (ftUS) NAD83 (National Spatial Reference System 2011) NAD83(2011) SPCS83 Virginia North zone (US survey foot) 1 easting X ftUS east 2 northing Y ftUS north Custom Unclassified Data is available online for bulk and 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. https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=10232/details/10232 2024 Organization NOAA Office for Coastal Management Customized Download Create custom data files by choosing data area, map projection, file format, etc. A new metadata will be produced to reflect your request using this record as a base. Not Applicable Zip https://prd-tnm.s3.amazonaws.com/index.html?prefix=StagedProducts/Elevation/OPR/Projects/VA_NorthernVA_B22/VA_NorthernVA_3_B22/TIFF/ 2024 Organization U.S. Geological Survey Bulk Download Bulk download of data files in GeoTiff format, VA State Plane North NAD83(2011), US feet coordinates and elevations in NAVD88 (Geoid18) feet. GeoTIFF https://coast.noaa.gov/dataviewer/ NOAA's Office for Coastal Management (OCM) Data Access Viewer (DAV) Online Resource HTML The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer. https://prd-tnm.s3.amazonaws.com/StagedProducts/Elevation/metadata/VA_NorthernVA_B22/USGS_VA_NorthernVA_B22_Project_Report.pdf USGS Project Report Online Resource pdf Link to the USGS Project Report that provides information about the project, vertical accuracy results, and the point classes and sensors used. https://prd-tnm.s3.amazonaws.com/StagedProducts/Elevation/metadata/VA_NorthernVA_B22/VA_NorthernVA_3_B22/reports/VA_NorthernVA_3_B22_LidarMappingReport.pdf Lidar Report Online Resource pdf Link to the lidar report. https://prd-tnm.s3.amazonaws.com/index.html?prefix=StagedProducts/Elevation/metadata/VA_NorthernVA_B22/VA_NorthernVA_3_B22/ USGS Additional Info Online Resource Link to the reports, breaklines, metadata, and spatial metadata. Leica HexMap; GeoCue; Windows 10 This data set was tested to meet ASPRS Positional Accuracy Standard for Digital Geospatial Data (2014) for a 10 cm RMSEz Vertical Accuracy Class. USGS DEM Determined Vertical Accuracy: Non-Vegetated Vertical Accuracy (NVA) = 4.35 cm RMSE Vegetated Vertical Accuracy (VVA) = 18.04 cm at the 95th Percentile Datasets contain complete coverage of tiles. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. There are no void areas or missing data. The raw point cloud is of good quality and data passes Non-Vegetated Vertical Accuracy specifications. Data covers the DPA specified for this project. Yes Unknown Yes NCEI-NC Data is backed up to cloud storage. The NOAA Office for Coastal Management (OCM) ingested references to the USGS GeoTIFF files that are hosted on Amazon Web Services (AWS), into the Digital Coast Data Access Viewer (DAV). The DAV accesses the raster data as it resides on AWS. USGS GeoTIFF Files Organization USGS Publisher https://prd-tnm.s3.amazonaws.com/index.html?prefix=StagedProducts/Elevation/OPR/Projects/VA_NorthernVA_B22/VA_NorthernVA_3_B22/TIFF/ USGS GeoTIFF Files 1 The boresight was completed prior to project execution. The following steps describe the Raw Data Processing process: 1) Technicians processed the raw data to LAS format flight lines using the final GNSS/IMU solution. This LAS data set was used as source data for lidar matching. 2) Technicians utilized commercial and proprietary software packages to analyze how well flight line overlaps match for the entire lift and adjusted as necessary until the results met the project specifications. 3) Once all lifts were completed with lidar matching, the technicians checked and corrected the vertical misalignment of all flight lines and also the matching between data and ground truth. The relative accuracy was less than or equal to 6 cm RMSEz within individual swaths and less than or equal to 8 cm RMSEz or within swath overlap (between adjacent swaths). 4) The technicians ran a final vertical accuracy check of the flight lines against the surveyed check points after the z correction to ensure the requirement of NVA = 19.6 cm 95% Confidence Level (Required Accuracy) was met. Point classification was performed according to USGS Lidar Base Specification, and breaklines were collected for water features. Bare-earth DEMs were exported from the classified point cloud using collected breaklines for hydroflattening. 2023-01-01T00:00:00 2 LAS Point Classification: The point classification is performed as described below. The bare-earth surface is then manually reviewed to ensure correct classification on the Class 2 (Ground) points. After the bare-earth surface is finalized, it is then used to generate all hydro-breaklines through heads-up digitization. All Class 2 (Ground) lidar data inside of the Lake Pond and Double Line Drain hydro-flattened breaklines were then classified to Class 9 (Water) using LP360 functionality. A buffer of 1 ft was also used around each hydro-flattened feature to classify these Class 2 (Ground) points to Class 20 (Ignored Ground). All Lake Pond Island and Double Line Drain Island features were checked to ensure that the Class 2 (Ground) points were reclassified to the correct classification after the automated classification was completed. All data was manually reviewed and any remaining artifacts removed using functionality provided by LP360, TerraScan and TerraModeler. Global Mapper was used as a final check of the bare-earth dataset. GeoCue was then used to create the deliverable industry-standard LAS files. Sanborn Map Company, Inc. proprietary software was used to perform final statistical analysis of the classes in the LAS files, on a per tile level to verify final classification metrics and full LAS header information. 2023-01-01T00:00:00 3 Data was tested at 0.48 meter aggregate nominal pulse spacing and at 4.3 aggregate points per meter. The aggregate nominal pulse spacing was tested on classified tiled LAS using geometrically reliable first-return points without overlap. ANPS was tested using Delaunay Triangulation that produced average point spacing between all nearest neighbors. 2023-01-01T00:00:00 4 Maximum Surface Height Rasters were produced as ancillary data from the classified lidar point cloud in order to evaluate the withheld bit flag proof of performance for points that cannot be reasonably interpreted as valid surface returns. These were produced using all returns, withheld flagged points excluded, and using the highest elevation point value from each pixel. These rasters are 32-bit, floating point format and delivered as GeoTIFF files per tile. Cell size of the MSHR is 2 feet. MSHR are generated from the point cloud data and will not be altered after creation nor will there be further maintenance on this product. 2023-01-01T00:00:00 5 Swath Separation Imagery was produced for the entire project area. Swath separation images use color-coding to illustrate differences in elevation (z-) values where swaths overlap. The color-coded images are semi-transparent and overlay the lidar intensity image. They are ancillary data used as visual aids to more easily identify regions within point cloud datasets that may have suspect interswath alignment or other geometric issues. Imagery was created using last returns with all classification and bit flags, except for noise and withheld bit flag are included. Images are derived from a TIN and have a 50% transparent RGB layer over lidar intensity. Color intervals are as follows for QL2 data: 0-8cm, green; 8-16cm, yellow; >16cm, red. These files were produced as GeoTIFF tiles using a cell size of 4 feet. SSI are generated from the point cloud data and will not be altered after creation nor will there be further maintenance on this product. 2023-01-01T00:00:00 6 Hydro-flattened Bare-earth DEM Process: Class 2 (Ground) lidar points in conjunction with the hydro breaklines were used to create a 2 foot hydro-flattened Raster DEM. Using automated scripting routines within LP360, a GeoTIFF file was created for each tile. Each surface is reviewed using Global Mapper to check for any surface anomalies or incorrect elevations found within the surface. 2023-01-01T00:00:00 7 The NOAA Office for Coastal Management (OCM) created references to the USGS GeoTIFF files that were ingested into the NOAA Digital Coast Data Access Viewer (DAV). No changes were made to the data. The DAV will access the raster data as it resides on Amazon Web Services (AWS). This is the location of the GeoTIFF files that are being accessed: https://prd-tnm.s3.amazonaws.com/index.html?prefix=StagedProducts/Elevation/OPR/Projects/VA_NorthernVA_B22/VA_NorthernVA_3_B22/TIFF/ 2024-12-12T00:00:00 Organization Office for Coastal Management OCM https://ror.org/05v14bq57 2234 South Hobson Avenue Charleston SC 29405-2413 https://www.coast.noaa.gov/ 73990 Data Set Cross Reference gov.noaa.nmfs.inport:74010 Rebecca Mataosky 2024-12-12T19:46:19 SysAdmin InPortAdmin 2026-03-04T19:17:17 2024-12-12 OCM Partners OCMP 1002 Public No No 2024-12-09 1 Year 2025-12-09