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Data Series 847

Coastal Bathymetry and Backscatter Data Collected in 2012 from the Chandeleur Islands, Louisiana

Index
Abstract
Introduction
Survey Overview and acquisition
Data Processing
Error Analysis
Survey Products
Data Downloads
Logs
Acronyms
References Cited
 

Data Downloads

The bathymetry grid (DEM) is presented in GeoTiff format and can be opened directly in Esri ArcGIS 10.0 or higher. The map documents and shapefiles provided in this report were created in Esri ArcGIS 10.0.5 and can be found in the GIS Project folder. To open this folder in Esri ArcGIS, right-click and choose "Save As". The folder contains the .mxd file and all associated vector and raster data. The data layers provided may also be viewed using the free GIS viewer ArcGIS Explorer (http://www.esri.com/software/arcgis/explorer). All data files presented in this report use the projected coordinate system North American Datum of 1983 (NAD83), Universal Transverse Mercator (UTM) Zone 16 North (16N), and all elevations are North American Vertical Datum of 1988 (NAVD88) orthometric heights, derived from the GEOID09 geoid model unless otherwise indicated. Do not use these data for navigational purposes.

Preview File Description File Format Download File Metadata
Thumbnail image showing preview of 50m bathymetry DEM of the Chandeleur Islands surveyed in 2012

Esri ArcGIS project

Esri files Chan12-GIS.zip (50 MB) Included with download
Bathymetry DEM
50-m cell size

GeoTIFF
32-bit floating point

Chan12_DEM.zip (0.154 MB) Included with download
Thumbnail image showing preview of 1-m backscatter grid of the Chandeleur Islands surveyed in 2012 Backscatter Mosaic
1-m resolution
GeoTIFF
32-bit floating point
12BIM03_IFS_Mosaic.zip (51 MB)

Included with download

Thumbnail image showing preview of the swath bathymetry tracklines surveyed in 2012 Swath samples
5-m BASE resolution
ASCII Chan12_IFB_xyz.zip (14 MB) Included with download
Swath tracklines Esri shapefile 12BIM03_IFB_tracklines.zip (1.60 MB) Included with download
Thumbnail image showing preview of the single-beam bathymetry tracklines surveyed in 2012 Singlebeam soundings ASCII Chan12_SBB_xyz.zip (51 MB) Included with download
Singlebeam tracklines Esri shapefile 12BIM04_SBB_tracklines.zip (1.89 MB) Included with download

A Note on Coordinate Systems

WGS84 and NAD83 have been revised several times resulting in coordinate shifts of as much as several meters in x, y, and z. The revision is indicated by the designator following the name (G1150 following WGS84, for example). Care should be taken using software that does not distinguish between the different datum versions; lack of designator is a warning sign that software does not support three-dimensional (3D) datum shifts properly. Users should pay particular attention to the accompanying metadata files to ensure that the data are properly georeferenced. In particular, note that most current GIS software (including ArcGIS 9.3) cannot properly transform high-resolution elevation data from one 3D datum to another (such as WGS84 G1150 to NAD83 CORS96) without introducing errors on the order of 1 m to 2 m in x,y, and z.

The data in this report are provided with a UTM zone 16 horizontal datum of WGS84 G1150 (equivalent to ITRF2000) and converted to NAD83 with vertical datum of NAVD88.  The vertical component was transformed using NOAA's VDatum tool (http://vdatum.noaa.gov/), by applying GEOID09 to obtain orthometric elevation.

 

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