Department of Commerce (DOC), National Oceanic and Atmospheric Adminis, 20011001, U.S. Vector Shoreline extracted from NOAA Nautical Chart 11369: Lakes Pontchartrain and Maurepas: kapp number: 54, NOAA's Ocean Service, Office of Coast Survey, Silver Spring, MD.This is part of the following larger work.Online Links:
Williams, S.J., Reid, J.M., Cross, V., and Polloni, C., 2003, Coastal Erosion and Wetland Change in Louisiana: Selected USGS Products: Digital Data Series 79, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Field Center, Woods Hole, MA.Online Links:
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.01. Longitudes are given to the nearest 0.01. Latitude and longitude values are specified in decimal seconds.
The horizontal datum used is NAD 83.
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.
| Value | Definition |
|---|---|
| Mean High Water Line (MHWL) | The line on a chart which represents the intersection of land with the water surface at the elevation of mean high water. |
| Mean Lower Low Water Line (MLLW) | The line on a chart which represents the intersection of land with the water surface at the elevation of mean lower low water. |
Sequential unique whole numbers that are automatically generated.
Coordinates defining the features.
National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), Office of Coast Survey (OCS), Coast Survey Development Laboratory (CSDL)
Chief, Cartographic & Geospatial Technology Program
1315 East-West Hwy. N/CS12
Silver Spring, MD 20910
USA
(301) 713-2645 (voice)
The data is intended for use as a vector query tool that represents the charted shoreline of the area. Vector shoreline data are beneficial in many GIS applications. Coastal zone managers need shoreline data for response to natural and manmade disasters, in environmental decision making, and for boundary purposes. Internally, the National Geodetic Survey (NGS) Remote Sensing Division and the OCS Hydrographic Surveys Division use the vector data for change analysis. Since the NOS charts contain shoreline in raster format these data are needed to clip and query from in a GIS environment. To ensure a match to charted shoreline, that data set is derived from the nautical chart.
National Oceanic and Atmospheri, National Ocean Service (NOS), Office of , 19950101, Nautical Chart: Nautical Charts kapp number 54, NOAA's Ocean Service, Office of Coast Survey (OCS), Silver Spring, MD.
Person who carried out this activity:
National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), Office of Coast Survey (OCS), Coast Survey Development Laboratory (CSDL)Data sources used in this process:
Chief, Cartographic & Geospatial Technology Program
1315 East West Hwy. N/CS12
Silver Spring, MD 20910
USA
(301) 713-2645 (voice)
Person who carried out this activity:
U.S. Geological Survey
c/o Jamey M. Reid
IT Specialist (Data Management)
Woods Hole Field Center
Woods Hole, MA 025453-1598
USA
(508) 457-2204 (voice)
(508) 457-2310 (FAX)
jreid@usgs.gov
Person who carried out this activity:
VeeAnn Cross
U.S. Geological Survey
Marine Geologist
384 Woods Hole Rd.
Woods Hole, MA 02543-1598
508-548-8700x2251 (voice)
508-457-2310 (FAX)
Nautical charts are updated as part of an ongoing process to create a cartographic representation of the best available data collected through the years employing a variety of data collection technology and techniques and provided to the Office of Coast Survey using numerous different scales, datums, and projections. As technology has allowed for a drastic increase in positional accuracy historical data has not been superseded for many areas. The availability of digital chart products and Differential Global Positioning System (DGPS) has drastically changed navigation. Navigation systems using DGPS for locating a vessel's position on the earth have put mariners in a unique predicament due to a false perception of greater positional accuracy of features portrayed on the charts. In many cases, the DGPS is more accurate than the surveying technology that was used to put the soundings and features on the nautical chart, paper or raster. The data accuracy is checked against its source nautical chart only. It is in no way intended for navigational uses or to be used as the legal shoreline. The data accuracy is checked against its source nautical chart only. NOAA assumes no liability for use of this data.
Charts use multiple vertical datums (Mean higher high water [MHHW]; Mean high water [MHW]; Mean sea level [MSL]; Mean low water [MLW]; Low water datum [LWD]; Mean lower low water [MLLW]; Gulf Coast low water datum [GCLWD].) The NOAA Nautical chart manual has an extensive description of the vertical datum used. Sounding datums used in coastal areas for nautical charting are determined by local observations, ideally over a period of 19 years. The official time period over which tide observations are taken to obtain mean values for tidal datums has been standardized by NOS. The present National Tidal Datum Epoch is from 1960 through 1978. There have been two epochs used previously this century; 1924 through 1942, and 1941 through 1959. The individual chart title block documents the datum used for that chart. Nautical charts are updated as part of an ongoing process to create a cartographic representation of the best available data collected through the years employing a variety of data collection technology and techniques. As technology has allowed for a drastic increase in survey accuracy historical data has not been superseded for many areas. Therefore, shoreline extracted from a single chart may contain multiple collection dates and be only accurate as the technology used to collect it allowed. The data accuracy is checked against its source nautical chart only. It is in no way intended for navigational uses or to be used as the legal shoreline. NOAA assumes no liability for use of this data.
A complete list of selection criteria, generalization, and definitions used to determine what is included in the data set are completely outlined in the NOAA Nautical Chart Manual Seventh (1992) Edition. On a 1:40,000 scale chart, a feature could have a potential error of 40 to 80 meters (about 130-160 feet) due to scale alone. This is often the cause of the "ship on the pier" situation, where the vessel tied up at the pier appears on the navigation system to be on the pier rather than alongside. Another source of this type of discrepancy is that symbols on a chart of a given scale may be a representation for multiple real features that are too close together to be shown at chart scale. Similarly, symbols may be displaced from their original location for legibility and presentation. The NOAA Nautical Chart Manual has an extensive description of the horizontal datum.
The projection of the source data set has been altered to non-projected geographic positions. The data set contains topology but has not been corrected for spatial relationships between charts. While the topology is good, lines may not always intersect where intended. Polygons intersected by the neatline close along that border.
Are there legal restrictions on access or use of the data?
- Access_Constraints: none
- Use_Constraints:
- The data is intended for use as a tool for GIS analysis. It is in no way intended for navigational uses or to be used as the legal shoreline. The data accuracy is checked against its source nautical chart only. NOAA assumes no liability for use of this data.
National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), Office of Coast Survey (OCS), Coast Survey Development Laboratory (CSDL)
Chief, Cartography & Geospatial Technology Program
1315 East West Hwy. N/CS12
Silver Spring, MD 20910
USA
(301) 713-2645 (voice)
Downloadable Data
The data is intended for use as a tool for GIS analysis. It is in no way intended for navigational uses or to be used as the legal shoreline. The data accuracy is checked against its source nautical chart only. NOAA assumes no liability for use of this data.
| Data format: | Size: 0.164 |
|---|---|
| Network links: |
<http://historicals.ndc.noaa.gov/cm_vs_query.asp> |
National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), Office of Coast Survey (OCS), Coast Survey Development Laboratory (CSDL)
Chief, Cartography & Geosptial Technology Program
1315 East West Hwy. N/CS12
Silver Spring, MD 20910
USA
(301) 713-2645 (voice)