Data Management Plan

These data were collected for the Government of Guam Department of Public Works and the Government of Guam Office of Homeland

Security from February 18 through May 20, 2007. The data contained in these files contain topographic data collected by the CHARTS

system. The data points representing bare earth have been classified as such using TerraScan. The topographic lidar was collected

across the island of Guam to produce 2 foot contours and bathymetric lidar was collected to fill the areas where no data were

obtained during previous survey efforts. The bathymetric lidar data were collected from the land/water interface seaward to a

depth of 40 meters or laser extinction, whichever came first. This is a classified data set. Classification values are:

Class 1: Unclassified

Class 2: Ground

Class 11: Bathymetric points

Class 14: upland collected bathymetric points (green topo)

The data contain both first and last return lidar data. The topographic lidar data are vertically referenced to Mean Sea Level (MSL)

and the bathymetric lidar data are referenced to Mean Lower Low Water (MLLW).

Process Steps:

• 2007-11-14 00:00:00 - These data were collected using the CHARTS system. It is owned by the Naval Oceanographic Office and Operated through contract. The system collects topographic lidar data at 20 kHz and hydrographic data at 3 kHz. The system also collects RGB imagery at 1Hz. A CASI-1500 hyperspectral line scanner is integrated with the system as well. Aircraft position, velocity and acceleration information are collected through a combination of Novatel and POS A/V equipment. Raw data are collected and transferred to the office for downloading and processing in SHOALS GCS software. GPS data are processed using POSPac software and the results are combined with the lidar data to produce 3-D positions for each lidar shot. These data are edited using Fledermaus software where anomalous data are removed from the dataset. The edited data are written to the national grid system 1 km tiles using chartsLAS, a program written by NAVO. This program reads data from the original binary format files and produces separate ASCII files for first and last return data. Using a model calculated by NAVO, data were converted from ellipsoid to Mean Sea Level heights using the program datum_shift, written by NAVO. The LAS files output from chartsLAS were read into TerraScan and filters were applied to classify ground points. Points designated as ground are assigned a classification value "2" and all other points are assigned the classification value "1" which represents an unclassified state.
• 2014-08-01 00:00:00 - The NOAA Office for Coastal Management (OCM) received files in LAS format. The files contained LiDAR intensity and elevation measurements. OCM performed the following processing on the data for storage and provisioning purposes within Digital Coast: 1. The data were converted from UTM coordinates to geographic coordinates. 2. The bathymetric lidar classifications were set to class 11. 3. The LAS georeference header files were set to reflect the tidal vertical datums. 4. The LAS header fields were sorted by latitude and updated. 5. OCM exported the laz files to contours, converting into a polygon shapefile. OCM then used this polygon as a sea and land interface, classifying upland class 11 (bathymetric points) to class 14 (Green Topo, upland topography collected with the green laser which collected class 11); the sensor used to collect bathymetric lidar also collects topography upland but the newest classification shows the inaccurately mapped upland topography as class 14 points.

This data can be obtained on-line at the following URL: https://coast.noaa.gov/dataviewer;