NOAA Office for Coastal Management Coastal Inundation Digital Elevation Model: American Samoa

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 metadata record describes the Pago Pago Weather Service (PPG WSO) digital elevation model (DEM), which is a part of a series of DEMs produced for the National Oceanic and Atmospheric Administration Office for Coastal Management's Sea Level Rise and Coastal Flooding Impacts Viewer described above. The DEMs created for this project were developed using the NOAA National Weather Service's Weather Forecast Office (WFO) boundaries. This DEM includes the best available lidar known to exist at the time of DEM creation that met project specifications for the Pago Pago WSO, which includes the following islands in American Samoa: Tutuila, Aunu'u, Ofu, Olosega, Tau, and Rose Atoll. The DEM is derived from the following source. 1. 2012 American Samoa Lidar - acquired by NOAA and partners Hydrographic breaklines were delineated from LiDAR intensity imagery generated from the LiDAR datasets. The final DEM is hydro flattened such that water elevations are less than or equal to -0.5 meters. The DEM is referenced vertically to the American Samoa Vertical Datum of 2002 (ASVD02) with vertical units of meters and horizontally to the North American Datum of 1983 (PACP00). The resolution of the DEM is 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.

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The data set used to construct this DEM is available via the following: 1. 2012 American Samoa Lidar http://www.coast.noaa.gov/dataviewer/index.html?action=advsearch&qType=in&qFld=ID&qVal=2490

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Map_Projection:

Map_Projection_Name: NAD 1983 (PACP00) UTM Zone 2S

Transverse_Mercator:

Scale_Factor_at_Central_Meridian: 0.9996

Longitude_of_Central_Meridian: -159.0

Latitude_of_Projection_Origin: 0.0

False_Easting: 500000.0

False_Northing: 0.0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: row and column

Coordinate_Representation:

Abscissa_Resolution: 3.000000

Ordinate_Resolution: 3.000000

Planar_Distance_Units: meter

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983

Ellipsoid_Name: Geodetic Reference System 80

Semi-major_Axis: 6378137.000000

Denominator_of_Flattening_Ratio: 298.257222101

Vertical_Coordinate_System_Definition:

Altitude_System_Definition:

Altitude_Datum_Name: ASVD02

Altitude_Resolution: 0.001

Altitude_Distance_Units: meters

Altitude_Encoding_Method: Explicit elevation coordinate included with horizontal coordinates

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

None

The dataset is provided as is, without warranty to its performance, merchantable state, or fitness for any particular purpose. The entire risk associated with the results and performance of this dataset is assumed by the user. This dataset should be used strictly as a planning reference and not for navigation, permitting, or other legal purposes.

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.

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.