Offshore baseline for the Louisiana coastal region generated to calculate shoreline change rates
Sandy ocean beaches are a popular recreational destination, often surrounded by communities containing valuable real estate. Development is on the rise despite the fact that coastal infrastructure is subjected to flooding and erosion. As a result, there is an increased demand for accurate information regarding past and present shoreline changes. To meet these national needs, the Coastal and Marine Geology Program of the U.S. Geological Survey (USGS) is compiling existing reliable historical shoreline data along open-ocean sandy shores of the conterminous United States and parts of Alaska and Hawaii under the National Assessment of Shoreline Change project.
There is no widely accepted standard for analyzing shoreline change. Existing shoreline data measurements and rate calculation methods vary from study to study and prevent combining results into state-wide or regional assessments. The impetus behind the National Assessment project was to develop a standardized method of measuring changes in shoreline position that is consistent from coast to coast. The goal was to facilitate the process of periodically and systematically updating the results in an internally consistent manner.
U.S. Geological Survey, 2017, Offshore baseline for the Louisiana coastal region generated to calculate shoreline change rates: data release DOI:10.5066/F78P5XNK, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.
Himmelstoss, E.A., Kratzmann, M.G., and Thieler, E.R., 2017, National Assessment of Shoreline Change— A GIS compilation of Updated Vector Shorelines and Associated Shoreline Change Data for the Gulf of Mexico Coast: data release DOI:10.5066/F78P5XNK, U.S. Geological Survey, Reston, VA.
What coordinate system is used to represent geographic features?
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude.
Latitudes are given to the nearest 0.000001.
Longitudes are given to the nearest 0.000001.
Latitude and longitude values are specified in Decimal degrees.
The horizontal datum used is D_WGS_1984.
The ellipsoid used is WGS_1984.
The semi-major axis of the ellipsoid used is 6378137.000000.
The flattening of the ellipsoid used is 1/298.257224.
Reference baseline used by the Digital Shoreline Analysis System (DSAS) to calculate rate-of-change statistics
(Source: U.S. Geological Survey)
Internal feature number.
Sequential unique whole numbers that are automatically generated.
Coordinates defining the features.
Field required by the Digital Shoreline Analysis System (DSAS) software. DSAS uses this value to determine the ordering sequence of transects when the baseline feature contains multiple segments. Individual segments are numbered sequentially alongshore.
(Source: U.S. Geological Survey)
Range of values
The entity and attribute information provided here describes the tabular data associated with the dataset. Please review the individual attribute descriptions for detailed information.
This dataset includes a reference baseline used by the Digital Shoreline Analysis System (DSAS) to calculate rate-of-change statistics for the Louisiana coastal region from the Chandeleur Islands to Raccoon Point, on Isles Dernieres at the mouth of Caillou Bay. This baseline layer serves as the starting point for all transects cast by the DSAS application. The transects intersect each shoreline and establish measurement points used to calculate shoreline-change rates.
Rates of long-term and short-term shoreline change were generated in a GIS using the DSAS version 4.3- An ArcGIS extension for calculating shoreline change: U.S. Geological Survey Open-File Report 2008-1278, Thieler, E.R., Himmelstoss, E.A., Zichichi, J.L., and Ergul, Ayhan.
A baseline was constructed offshore from the time series of shoreline positions using standard editing tools in ArcMap v10.2. The baseline was positioned to conform to changes in the combined orientation of the shorelines alongshore. This was done so that the transects, which are generated by the Digital Shoreline Analysis System v4.3 from the baseline, would intersect perpendicular to the general trend of the shorelines.
This process step and all subsequent process steps, unless otherwise noted, were performed by the same person - M.G. Kratzmann.
Person who carried out this activity:
U.S. Geological Survey
384 Woods Hole Road
Woods Hole, MA
Date: 25-Aug-2015 (process 2 of 5)
The baseline feature class was imported into a personal geodatabase in ArcCatalog v10.2 by right-clicking on the geodatabase > Import (feature class for shoreline file and table for uncertainty table) for use with the Digital Shoreline Analysis System (DSAS) v4.3 software to perform rate calculations.
Date: 27-Aug-2015 (process 3 of 5)
The baseline feature class was exported from a personal geodatabase to a shapefile in ArcCatalog (v10.2) by performing a right-mouse click on the data layer > export > to shapefile (single).
Date: 27-Aug-2015 (process 4 of 5)
The baseline shapefile was projected in Esri's ArcToolbox (v10.2) > Data Management Tools > Projections and Transformations > Project. parameters: input projection - NAD 1983 State Plane Louisiana South FIPS 1702 (Meters); output projection- geographic coordinates (WGS 84); transformation = NAD_1983_To_WGS_1984_1.
Date: 25-Aug-2017 (process 5 of 5)
Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog.
Person who carried out this activity:
Morton, Robert A., Miller, Tara L., and Moore, Laura J., 2004, National Assessment of Shoreline Change: Part 1 Historical Shoreline Changes and Associated Coastal Land Loss along the U.S. Gulf of Mexico: Open-File Report 2004-1043, U.S. Geological Survey, Reston, VA.
Thieler, E.R., Himmelstoss, E.A., Zichichi, J.L., and Ergul, A., 2009, Digital Shoreline Analysis System (DSAS) version 4.0 - An ArcGIS extension for calculating shoreline change: Open-File Report 2008-1278, U.S. Geological Survey, Reston, VA.
Other_Citation_Details:Current version of software at time of use was 4.3
Himmelstoss, E.A., Kratzmann, M.G., and Thieler, E.R., 2017, National Assessment of Shoreline Change: Summary Statistics for Updated Vector Shorelines and Associated Shoreline Change Data for the Gulf of Mexico and Southeast Atlantic Coasts: Open-File Report 2017-1015, U.S. Geological Survey, Reston, VA.
How well have the observations been checked?
The attribute in this layer is based on the requirements for use within the Digital Shoreline Analysis System (DSAS) software (USGS Open-File Report 2008-1278). The data have been quality checked.
How accurate are the geographic locations?
The baseline serves as a reference point for transects cast by the Digital Shoreline Analysis System (DSAS) software. It does not correspond to any real-world feature.
Where are the gaps in the data? What is missing?
This baseline file is complete and contains the baseline segments used to cast transects along sections of the Louisiana coastal region where lidar shoreline position data were available and additional shoreline data are present to calculate either a short- or long-term rate.
Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials.
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
These files (.cpg, .dbf, .prj, .sbn, .sbx, .shp, .shp.xml, and .shx) are a collection of files with a common filename prefix and must be downloaded and stored in the same directory. Together they are the components of the shapefile and include FGDC compliant metadata.
in format Shapefile
(version ArcGIS 10.2)
Esri polyline shapefile