2018 USGS Lidar DEM: Delaware County, OH

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners.

To the extent possible under law, the U.S. Government has waived all copyright and related or neighboring rights to this dataset.

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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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.

Microsoft Windows 10 Version 1607 (Build 14393.2189); ArcMap 10.4; ArcCatalog 10.4; TerraModeler ver. 18; Geocue 2017.2.20.0, POSPac Software v. 5.3, IPAS Pro v.1.35, Novatel Inertial Explorer v8.60.6129, TerraMatch v.18.03, Leica Cloud Pro v1.2.3, TerraScan v.18.18

Not provided

The project specifications require the accuracy (ACCz) of the derived DEM be calculated and reported in two ways: 1. The required NVA is: 19.6 cm at a 95% confidence level, derived according to NSSDA, i.e., based on RMSE of 10 cm in non-vegetated land cover classes. This is a required accuracy. The NVA was tested with 35 checkpoints located in non-vegetated areas. 2. Vegetated Vertical Accuracy (VVA): VVA shall be reported for vegetated land cover classes. The target VVA is: 30 cm at the 95th percentile, derived according to ASPRS Guidelines, Vertical Accuracy Reporting for Lidar Data, i.e., based on the 95th percentile error in all vegetated land cover classes combined. This is a target accuracy. The VVA was tested with 25 checkpoints located in vegetated areas. The checkpoints were distributed throughout the project area and were surveyed using GPS techniques. AccuracyZ has been tested to meet 19.6 cm or better Non-Vegetated Vertical Accuracy at 95% confidence level using RMSE(z) x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASRPS Guidelines.

Tested 0.054 meters NVA at a 95% confidence level using RMSE(z) 0.028 meters x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA). The NVA of the DEM was calculated using 35 independent checkpoints located in non-vegetated land cover categories.

Tested 0.201 meters VVA was calculated using 25 checkpoints located in vegetated land cover categories at the 95th percentile, derived according to ASPRS Guidelines, Vertical Accuracy Reporting for Lidar Data. Tested against the DEM.

VVA Errors larger than 95th percentile include:

Point 3004, Easting 1095281.875, Northing 1995606.127, Z-Error 0.256 Meters

Point 3016, Easting 1112147.216, Northing 1995286.821, Z-Error 0.210 Meters

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 DEM is of good quality and data passes Non-Vegetated and Vegetated Vertical Accuracy specifications.

Data covers the entire area specified for this project.

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.