2012-2013 U.S. Geological Survey LiDAR: Territory of Guam

Territory of Guam, LiDAR Task G11PD01189

This task order is for production of surface model products of The Territory of Guam. The models are produced from data acquired using airborne Light Detection and Ranging (LiDAR) sensors. The data is calibrated, classified and processed to produce surface models and products including Classified LAS, bare earth Digital Elevation Models (DEM), intensity raster images, shapefiles of road centerlines, forest canopy, building foot prints and breaklines of surface hydrology.

The United States Geological Survey requested surface data products and models that indicate surface conditions, drainage, vegetation, transportation routes and building structures to aid in analysis of land use, transportation, hydrologic, forest vegetation and recreational management.

Data and products were referenced to the Universal Transverse Mercator (UTM) Coordinate System - Zone 55, based on the World Geodetic System of 1984 (WGS84) in meters. The vertical reference is Guam Vertical Datum of 2004 (GUVD04) in meters. For provisioning and storage, NOAA OCM converted the horizontal coordinates to geographic decimal degrees and vertical coordinates referenced to ellipsoidal heights.

10366

A footprint of this data set may be viewed in Google Earth at: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/4939/supplemental/guam2012_usgs_m4939.kmz

A final lidar report can be found here:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/4939/supplemental/guam2012_usgs_m4939_lidarreport.pdf

An accuracy assessment for the project may be viewed here:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/4939/supplemental/guam2012_usgs_m4939_surveyreport.pdf

LiDAR points in LAS format (ASPRS Classes 1,2,7,9,10,17,18)

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

This data can be obtained on-line at the following URL:

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=4939;

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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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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. These data depict the heights at the time of the survey and are only accurate for that time.

None. However, users should be aware that temporal changes may have occurred since this dataset was collected and that some parts of these data may no longer represent actual surface conditions. Users should not use these data for critical applications without a full awareness of its limitations. Acknowledgement of the U.S. Geological Survey would be appreciated for products derived from these data.

Flown at 500 to 600 meters above ground level (AGL) the data has a horizontal accuracy of 0.11 meters (per manufacturers system specifications). ; Quantitative Value: 0.11 meters, Test that produced the value: Per manafacturers system specifications.

Ground survey check points were collected by AeroMetric, Inc. for use in vertical accuracy evaluation. In vertical accuracy evaluation, the ground survey check points of various ground cover categories are compared to vertical values of a TIN or DEM derived from the LiDAR data, differences in elevation are calculated to establish a RMSE.

Check point differences beyond the 95th Percentile of all data points are investigated to determine if there is an indication of problems with the data. This data set did not include any vertical differences significantly beyond the 95th Percentile value of check point differences.

Ground survey check points were made in February and March of 2012. Ground cover categories include Urban, Open Terrain, Tall Weeds, Brush and Forest. Separate check points were made for use in establishing point cloud position.

; Quantitative Value: 0.08 meters, Test that produced the value: Tested 8.0 cm (0.262 ft) RMSEz of the LiDAR data in Open Terrain as tested against the Triangulated Integrated Network (TIN).

; Quantitative Value: 0.157 meters, Test that produced the value: Tested 15.7 cm (0.515 ft) FVA at the 95% confidence level of the LiDAR data in open terrain as tested against the Triangulated Integrated Network (TIN).

; Quantitative Value: 0.087 meters, Test that produced the value: Tested 8.7 cm (0.285 ft) RMSEz in Open Terrain as tested against the DEM.

; Quantitative Value: 0.171 meters, Test that produced the value: Tested FVA of 17.1 cm (0.561 ft) at the 95% confidence level in Open Terrain as tested against the DEM.

; Quantitative Value: 0.154 meters, Test that produced the value: Tested 15.4 cm (0.505 ft) SVA at the 95th Percentile in the Open Terrain category against the DEM.

; Quantitative Value: 0.30 meters, Test that produced the value: Tested 30.0 cm (0.984 ft) SVA at the 95th Percentile in the Tall Weeds category against the DEM.

; Quantitative Value: 0.227 meters, Test that produced the value: Tested 22.7 cm (0.745 ft) SVA at the 95th Percentile in the Brush category against the DEM.

; Quantitative Value: 0.152 meters, Test that produced the value: Tested 15.2 cm (0.499 ft) SVA at the 95th Percentile in the Forest category against the DEM.

; Quantitative Value: 0.099 meters, Test that produced the value: Tested 9.9 cm (0.324 ft) SVA at the 95th Percentile in the Urban category against the DEM.

; Quantitative Value: 0.218 meters, Test that produced the value: Tested 21.8 cm (0.715 ft) CVA at the 95th Percentile in All Ground categories against the DEM.

The lidar data is visually inspected for completeness to ensure that are no void areas or missing data.

All formatted data cover the entire area specified for this project and are validated using a combination of commercial lidar processing software, GIS software, and proprietary programs to ensure proper formatting and loading prior to delivery.