Offshore bathymetry for Louisiana 2 Meters

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Frequently-anticipated questions:

What does this data set describe?

    Title: Offshore bathymetry for Louisiana 2 Meters
    This is a line data set depicting the offshore bathymetry for Louisiana. The contour interval is 2 meters. These data were derived from point depths depicted on NOAA Navigation charts. The depths on the NOAA charts are typically relative to 'mean low Gulf' levels, so these depths are conservative.
    These metadata describe the Arc/Info coverage of name 'congeog3dlbth' and the shapefile of the same name derived from it. These metadata also describe the dataset 'bathymetry' which is how this data set was named on the 'Louisiana GIS CD: A Digital Map of the State.'

    The metadata for this data set are encapsulated into several documents and graphics files. The metadata are not complete if you did not receive the following files along in the data set:

    congeog3dlbth.mtd - this metadata in mp (metadata parser) compatible ASCII text form
    congeog3dlbth.html - this metadata in HTML form
    congeog3dlbth_faq.html - this metadata presented as Questions and Answers
    congeog3dlbth.sgml - this metadata in SGML form
    congeog3dlbth1.gif - thumbnail graphic of data set
    The attribute and/or geometric component(s) of the data are provided as Arc export (.e00) file(s) and the corresponding three part (.shp, .shx, .dbf) shapefile(s) or standalone .dbf file(s) in the case an export file is a standalone INFO file. You should have received the following as part of the dataset:
    congeog3dlbth.prj - coordinate system definition file for shape

  1. How should this data set be cited?

    Louisiana Oil Spill Coordinator's Office (LOSCO), 1999, Offshore bathymetry for Louisiana 2 Meters.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -93.951630
    East_Bounding_Coordinate: -88.821663
    North_Bounding_Coordinate: 30.369144
    South_Bounding_Coordinate: 28.541408

  3. What does it look like?

    <URL:congeog3dlbth1.gif> (GIF)
    thumbnail graphic of data set

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: Apr-1990
    Ending_Date: Jun-1994
    Range of publication dates of NOAA charts from which depths were digitized.

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • String (518)

    2. 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 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

      Altitude_Resolution: 1.000000
      Explicit elevation coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    arc attribute table for congeog3dlbth (Source: 3001, Inc.)

    depth that contour delineates (Source: 3001, Inc.)

    Range of values

    type of contour line (Source: 3001, Inc.)

    intermediateindicates every 2 meter contour line
    indexindicates every 10 meter contour line
    intermediate_depintermediate depression; 2 meter depression line
    index_depindex depression; 10 meter depression line

    Coordinates defining the features.


    Feature geometry. (Source: ESRI)

    Coordinates defining the features.



Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    LOSCO gratefully acknowledges the Coastal Morphology Lab, Coastal Studies Institute at LSU for providing the source data for production of this data set.

  3. To whom should users address questions about the data?

    Louisiana Oil Spill Coordinator's Office
    c/o David Gisclair
    Technical Assistance Program (TAP) Director
    Louisiana Oil Spill Coordinator's Office
    Baton Rouge, LA 70804

    (225) 219-5800 (voice)
    (225) 219-5802 (FAX)

Why was the data set created?

A precursor to this dataset was developed as a surface for numerical wave modeling. This data set was developed in order that the 10 meter depth line could be extracted for other uses. The 10 meter depth line forms a regulatory boundary for dispersant use and in-situ burn pre-approval areas.

The user should be aware that meteorological events such as hurricanes may alter these depths or may have already have already altered the actual depths from those represented on the source NOAA charts. Furthermore, geomorphological processes due to sediment load are causing landward migration of isocontours at a rate of about 25 meters per year in the Mississippi River Delta Plain area (east and west of where the Mississippi empties out into the Gulf). Because these data are based on historical NOAA charts, the effects of this migration have not been captured.

How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    Date: 1999 (process 1 of 4)
    Bathymetric points were digitized from the NOAA (NOS) 1:80,000 navigation charts. Intergraph design files were produced for seven charts. Intergraph Terrain Analyst was used to produce a single file with 500 foot, interpolated grid points in ASCII format.

    Person who carried out this activity:

    Louisiana State University, Coastal Studies Institute
    c/o Dr. Greg Stone
    Louisiana State University
    Baton Rouge, LA 70803

    (225) 388-4728 (voice)

    Date: 15-Sep-1999 (process 2 of 4)
    The ASCII formatted file was transformed into a 2 meter (contour interval) vector file using TerraModel. Design files were exported and converted into ArcView shapefiles.

    Person who carried out this activity:

    3001, Inc.
    c/o Jeff Lower
    3655 SW 2nd Avenue, Suite 3-C
    Gainesville, FL 32607

    (352) 379-3001 (voice)

    Date: 27-Oct-1999 (process 3 of 4)
    The shapefile in UTM zone 15, NAD83 coordinates was edited to remove all contours landward of the first 2 meter depth contour that was continuous along the entire coast of Louisiana. The shapefile was converted to a line Arc/Info coverage, then projected to geographic coordinates NAD83. The arc intersect errors that were readily resolved (about half) were corrected. The resultant cover was converted to a shape and the arcs of the shape were merged on the depth value.

    Person who carried out this activity:

    3001, Inc.
    c/o Hugh Phillips
    3655 SW 2nd Avenue, Suite 3-C
    Gainesville, FL 32607

    (352) 379-3001 (voice)

    (process 4 of 4)
    Dataset copied.

    Data sources used in this process:

    •; Service=5151; User=usgs; Version=SDE.DEFAULT

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    These data represent contours that are oceanward of the the first 2 meter depth line that runs the entire length of the Louisiana Coast. All contours landward of this line have been deleted. The data set has a gap in the region of the Chandeleur Islands. At depths of 1000 meters and greater, the contour interval increases to 10 meters.

  5. How consistent are the relationships among the observations, including topology?

    Original digitized points were checked with a proximity (anomaly) filter. There are 17 intersection errors in the data set, primarily where neighboring contour lines make contact.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: none
These unaltered data may not be redistributed without all of the elements of the metadata listed in the Supplemental_Information section of this metadata document. It is recommended that third parties wishing to use these data obtain them from the Distributor listed in this metadata document.

If these data are altered or incorporated into another dataset, they are not to be redistributed without also: altering the name of the dataset, including a Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998) compliant metadata file that describes the dataset and reflects the alteration steps that makes the new dataset different from this one, and citing this dataset in the metadata as a source for the altered dataset using the source citation specified below.

If these digital data are used in the production of a report or in the compilation of a standalone printed map, then this dataset is to be cited in the report or on the map using the source citation specified below.

The following source citation is to be used when citing this dataset: LOSCO Environmental Baseline Inventory Dataset 'Louisiana Offshore Bathymetry, Geographic NAD83, LOSCO (1999) [congeog3dlbth]'

Users hereby agree to abide by the use and reproduction conditions specified above. By using the data described in these metadata, the user acknowledges that the terms and conditions of use have been read and that the user is bound by these criteria.

  1. Who distributes the data set? (Distributor 1 of 1)

    Louisiana Oil Spill Coordinator's Office
    c/o David Gisclair
    Technical Assistance Program (TAP) Director
    Louisiana Oil Spill Coordinator's Office
    Baton Rouge, LA 70804

    (225) 219-5800 (voice)
    (225) 219-5802 (FAX)

  2. What's the catalog number I need to order this data set?

    congeog3dlbth This is the explanation for the obtuse name: <URL:>

  3. What legal disclaimers am I supposed to read?

    The data herein, including but not limited to geographic data, tabular data, analytical data, electronic data structures or files, are provided "as is" without warranty of any kind, either expressed or implied, or statutory, including, but not limited to, the implied warranties or merchantability and fitness for a particular purpose. The entire risk as to the quality and performance of the data is assumed by the user. No guarantee of accuracy is granted, nor is any responsibility for reliance thereon assumed. In no event shall the Louisiana Oil Spill Coordinator's Office (LOSCO) be liable for direct, indirect, incidental, consequential or special damages of any kind, including, but not limited to, loss of anticipated profits or benefits arising out of use of or reliance on the data. The LOSCO does not accept liability for any damages or misrepresentation caused by inaccuracies in the data or as a result of changes to the data caused by system transfers or other transformations or conversions, nor is there responsibility assumed to maintain the data in any manner or form.

    These data have been developed from the best available sources. Although efforts have been made to ensure that the data are accurate and reliable, errors and variable conditions originating from physical sources used to develop the data may be reflected in the data supplied. Users must be aware of these conditions and bear responsibility for the appropriate use of the information with respect to possible errors, scale, resolution, rectification, positional accuracy, development methodology, time period, environmental and climatic conditions and other circumstances specific to these data. The user is responsible for understanding the accuracy limitations of the data provided herein. The burden for determining fitness for use lies entirely with the user. The user should refer to the accompanying metadata notes for a description of the data and data development procedures.

    Although these data have been processed successfully on computers at the LOSCO, no guarantee, expressed or implied, is made by LOSCO regarding the use of these data on any other system, nor does the act of distribution constitute or imply any such warranty. Distribution of these data is intended for information purposes and should not be considered authoritative for navigational, engineering, legal and other site-specific uses.

  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 25-Jun-2003

Metadata author:
3001, Inc.
c/o Mendi Johnson
GIS Analyst
3655 SW 2nd Ave., Suite 3C
Gainesville, FL 32607

(352) 379-3001 (voice)
(352) 377-4234 (FAX)

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

Metadata extensions used:

Generated by mp version 2.7.3 on Wed Jun 25 11:35:10 2003