2020 USGS Topobathy Lidar: Nisqually River Basin, WA

Product: Classified LAS 1.4 files, formatted to 85 individual 1,000m x 1,000m covering the Nisqually River Basin 2020 project area.

Geographic Extent: This dataset and derived products encompass an area covering approximately 13,189 acres of Western Washington.

Dataset Description: The Nisqually River Basin 2020 Lidar project called for the planning, acquisition, and processing of topobathy Lidar data collected to Quality Level 1 (QL1) standards. Project specifications are based on the U.S. Geological Survey National Geospatial Program LIDAR Base Specification, Version 2.1. The data was developed based on the NAD83 2011 horizontal datum and the NAVD88 Geoid 18 vertical datum. Data was projected in UTM Zone 10. Lidar data was delivered as calibrated and classified LAS 1.4 files. Non-Vegetated Vertical Accuracy (NVA) was assessed using 22 check points located on bare earth in clear, unobstructed areas. Submerged Topography accuracy was assessed using 86 check points collected as feasible in depths up to 1m. Vegetated Vertical Accuracy (VVA) was assessed using 14 check points in tall grass, forest, and shrubland landcover types. Single swath nominal pulse spacing (NPS) was designed to be 9.5 points per meter squared at nadir. Aggregate Nominal Pulse Spacing (ANPS) was calculated to be 36.59 points per meter squared using all valid first return points. Derived products include: Intensity Imagery, Topbathymetric Digital Elevation Models (DEMs), Hydro-flattened Bare Earth Digital Elevation Models (DEMs), Highest Hit Digital Surface Models (DSMs), 3D waters edge breaklines, and a bathymetric coverage shape.

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

This metadata supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV). For this data set, the DAV is leveraging the Entwine Point Tiles (EPT) 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 Nisqually River Basin 2020 contract. The lidar point cloud data were used to create classified lidar LAS files, intensity images, Topobathymetric DEMs, hydroflattened DEMs, highest hit surface models, and a bathymetric coverage shape.

USGS Contract No. G16PC00016 CONTRACTOR: NV5 Geospatial Ground Control Points were acquired and calibrated by NV5 Geospatial All lidar data acquisition, calibration, and follow-on processing were completed by NV5 Geospatial. </supplinf>

<lidar>

<ldrinfo>

<ldrspec>U.S. Geological Survey National Geospatial Program LIDAR Base Specification, Version 2.1</ldrspec>

<ldrsens>Riegl VQ-880-GII</ldrsens>

<ldrmaxnr>15</ldrmaxnr>

<ldrnps>9.5</ldrnps>

<ldrdens>0.32</ldrdens>

<ldranps>36.59</ldranps>

<ldradens>0.17</ldradens>

<ldrfltht>400</ldrfltht>

<ldrfltsp>140</ldrfltsp>

<ldrscana>40</ldrscana>

<ldrscanr>66.3</ldrscanr>

<ldrpulsr>245</ldrpulsr>

<ldrpulsd>1.5</ldrpulsd>

<ldrpulsw>0.45</ldrpulsw>

<ldrwavel>532</ldrwavel>

<ldrmpia>1</ldrmpia>

<ldrbmdiv>0.7</ldrbmdiv>

<ldrswatw>291</ldrswatw>

<ldrswato>60</ldrswato>

<ldrgeoid>Geoid 18</ldrgeoid>

</ldrinfo>

<ldrinfo>

<ldrspec>U.S. Geological Survey National Geospatial Program LIDAR Base Specification, Version 2.1</ldrspec>

<ldrsens>Riegl VQ-880-GII-IR</ldrsens>

<ldrmaxnr>15</ldrmaxnr>

<ldrnps>9.5</ldrnps>

<ldrdens>0.32</ldrdens>

<ldranps>36.59</ldranps>

<ldradens>0.17</ldradens>

<ldrfltht>400</ldrfltht>

<ldrfltsp>140</ldrfltsp>

<ldrscana>42</ldrscana>

<ldrscanr>Uniform Point Spacing</ldrscanr>

<ldrpulsr>145</ldrpulsr>

<ldrpulsd>3</ldrpulsd>

<ldrpulsw>0.9</ldrpulsw>

<ldrwavel>1064</ldrwavel>

<ldrmpia>1</ldrmpia>

<ldrbmdiv>0.2</ldrbmdiv>

<ldrswatw>307</ldrswatw>

<ldrswato>60</ldrswato>

<ldrgeoid>Geoid 18</ldrgeoid>

</ldrinfo>

<ldraccur>

<ldrchacc>0</ldrchacc>

<rawnva>0</rawnva>

<rawnvan>0</rawnvan>

</ldraccur>

<lasinfo>

<lasver>1.4</lasver>

<lasprf>6</lasprf>

<laswheld>Withheld (ignore) points are identified in these files using the standard LAS Withheld bit.</laswheld>

<lasolap>Swath "overage" points were identified in these files using the standard LAS overlap bit.</lasolap>

<lasintr>16</lasintr>

<lasclass>

<clascode>1</clascode>

<clasitem>Processed, but Unclassified</clasitem>

</lasclass>

<lasclass>

<clascode>2</clascode>

<clasitem>Bare earth ground</clasitem>

</lasclass>

<lasclass>

<clascode>7</clascode>

<clasitem>Low Noise</clasitem>

</lasclass>

<lasclass>

<clascode>9</clascode>

<clasitem>Water</clasitem>

</lasclass>

<lasclass>

<clascode>17</clascode>

<clasitem>Bridge Decks</clasitem>

</lasclass>

<lasclass>

<clascode>18</clascode>

<clasitem>High Noise</clasitem>

</lasclass>

<lasclass>

<clascode>22</clascode>

<clasitem>Temporal Exclusion</clasitem>

</lasclass>

<lasclass>

<clascode>40</clascode>

<clasitem>Submerged Topography</clasitem>

</lasclass>

<lasclass>

<clascode>41</clascode>

<clasitem>Water Surface</clasitem>

</lasclass>

<lasclass>

<clascode>45</clascode>

<clasitem>Water Column</clasitem>

</lasclass>

</lasinfo>

</lidar>

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

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 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 400 meters, an IMU error of 0.002 decimal degrees, and a GNSS positional error of 0.015 meters, this project was compiled to meet 0.050 m horizontal accuracy 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.

USGS Determined Vertical Accuracy

Non-Vegetated Vertical Accuracy (NVA) = 2.3 cm RMSE

Vegetated Vertical Accuracy (VVA) = 16.74 cm at the 95th Percentile

A visual qualitative assessment was performed to ensure data completeness. Bathymetric void areas have been interpolated. A bathymetric coverage shape has been provided as a separate deliverable. 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.

Data is backed up to tape and to cloud storage.

The Nisqually River Basin lidar was ingested into the Data Access Viewer for custom product generation by leveraging USGS hosted Entwine Point Tiles.