NOAA Office for Coastal Management Coastal Inundation Digital Elevation Model: Guam Weather Forecast Office (GUM WFO) - Guam

These data were created as part of the National Oceanic and Atmospheric Administration Office for Coastal Management's efforts to create an online mapping viewer called the Sea Level Rise and Coastal Flooding Impacts Viewer. It depicts potential sea level rise and its associated impacts on the nation's coastal areas. The purpose of the mapping viewer is to provide coastal managers and scientists with a preliminary look at sea level rise (slr) and coastal flooding impacts. The viewer is a screening-level tool that uses nationally consistent data sets and analyses. Data and maps provided can be used at several scales to help gauge trends and prioritize actions for different scenarios. The Sea Level Rise and Coastal Flooding Impacts Viewer may be accessed at: http://www.coast.noaa.gov/slr

This digital elevation model (DEM) is part of a series of DEMs produced for the National Oceanic and Atmospheric Administration Coastal Services Center's Sea Level Rise and Coastal Flooding Impacts Viewer described above. The DEM created for this project was developed using the NOAA National Weather Service's Weather Forecast Office (WFO) boundaries. This DEM falls in the Guam (GUM) WFO and shows the elevation data for the island of Guam. This DEM includes the best available lidar data known to exist at the time of DEM creation that met project specifications, for the island of Guam.

This DEM is derived from 2007 United States Army Corps of Engineers (USACE) lidar. Hydrographic breaklines were delineated using lidar intensity imagery generated from the lidar. The final DEM is hydro flattened such that water elevations are less than or equal to 0 meters.

The DEM is referenced vertically to the Guam Vertical Datum of 2004 (GUVD04) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). The resolution of the DEM is approximately 3 meters.

The NOAA Office for Coastal Management has developed high-resolution digital elevation models (DEMs) for use in the Center's Sea Level Rise And

Coastal Flooding Impacts internet mapping application. These DEMs serve as source datasets used to derive data to visualize the impacts of

inundation resulting from sea level rise along the coastal United States and its territories.

The dataset used to construct this DEM is publicly available via the NOAA Office for Coastal Management's Digital Access Viewer at this URL:

http://www.coast.noaa.gov/dataviewer/index.html?action=advsearch&qType=in&qFld=ID&qVal=551

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 or 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.

The DEM is derived from the source lidar data. Horizontal accuracy testing is not performed on the DEM. Lidar source data assumed to meet

1 meter horizontal accuracy.

The DEM is derived from the source lidar data. Vertical accuracy is not tested on the DEM. Project specifications require all source lidar

data used in constructing the DEM to meet FEMA Specifications for Flood Hazard Mapping. The vertical accuracy of the source lidar for this DEM,

2007 USACE Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBTCX) Topobathy Lidar: Guam, is 20 cm RMSE.

A visual qualitative check was performed to ensure data completeness. All available lidar data known at the time of DEM creation that meets

project specifications has been used to develop the DEM. Known data gaps may exist where lidar coverage was incomplete.

Data covers the tile scheme provided for the project area. Elevation data checked for anomalous elevation values outside expected range.