2023 NRCS QL1 Lidar DEM: Native Alaskan Villages (Kivalina)

Original Product: Hydroflattened Digital Elevation Model (DEM) data covering the Native Villages Kivalina project area.

Original Geographic Extent: This dataset and derived products encompass an area covering approximately 43,573 Acres of Kivalina.

Original Dataset Description: Lidar flight line swaths were processed to create 353 classified LAS 1.4 files delineated in 750m x 750m tiles tiles. Each LAS file contains lidar point information, which has been calibrated, controlled, and classified. Class 2 (ground) lidar points in conjunction with the hydro breaklines were used to create 353 0.5 meter hydro-flattened Raster DEMs delineated in 750m x 750m tiles tiles. Additional products include classified LAS files, intensity images, maximum surface height models, and 3D breaklines of rivers and lakes within the study area.

Ground Conditions: Ground condition was mostly free of snow and acquisition occurred free of smoke, fog and cloud cover.

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 GeoTIFF files hosted by USGS on Amazon Web Services.

The purpose of the lidar data was to produce a high accuracy 3D dataset that meets all necessary standards laid out by the 3D Elevation Program and the Native Villages Kivalina contract. The lidar point cloud data were used to create classified lidar LAS files, intensity images, hydro-flattened DEMs, maximum surface height models, and 3D breaklines of rivers and lakes within the study area.

Raster File Type = TIFF

Bit Depth/Pixel Type = 32-bit float

Raster Cell Size = 0.5 meter

Interpolation or Resampling Technique = Triangulated Irregular Network

Required Vertical Accuracy = 19.6 cm NVA

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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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

Lidar horizontal accuracy is a function of Global Navigation Satellite System (GNSS) derived positional error, flying altitude, and INS derived attitude error. The maximum GNSS positional error was derived from the laser trajectory using NV5's proprietary LAS processing software, Las Monkey. The obtained RMSEr value is multiplied by a conversion factor of 1.7308 to yield the horizontal component of the National Standards for Spatial Data Accuracy (NSSDA) reporting standard where a theoretical point will fall within the obtained radius 95 percent of the time. Based on a flying altitude of 2058 meters, a GNSS error of 0.027 meters, and an IMU error of 0.014 degrees, the Kivalina village in UTM zone 3 was produced to meet a horizontal accuracy of 1.558 meters, at the 95% confidence level.

This data set was produced to meet ASPRS Positional Accuracy Standard for Digital Geospatial Data (2014) for a 10-cm RMSEz Vertical Accuracy Class. Specifications for this project require that the VVA be 0.300 meters or better AccuracyZ at the 95th percentile.

USGS Determined DEM Vertical Accuracy:

Non-Vegetated Vertical Accuracy (NVA) = 3.55 cm RMSE

Vegetated Vertical Accuracy (VVA) = 26.39 cm at the 95th Percentile

A visual qualitative assessment was performed to ensure data completeness. No void areas or missing data exist. The raw point cloud is of good quality and data passes Non-Vegetated Vertical Accuracy specifications.

DEM files were tested by NV5 for vertical accuracy. All data is seamless from one tile to the next, no gaps or no data areas.

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.