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Coastline Extractor

World Vector Shoreline

  • Original source of data: Defense Mapping Agency (DMA) (now National Geospatial-Intelligence Agency (NGA).
  • World-wide coverage
  • Suitable for scales close to 250,000
  • Accuracy; requirement for this data is that 90% of all identifiable shoreline features be located within 500 meters (2.0mm at 1:250,000) circular error of their true geographic positions with respect to the preferred datum (WGS 84).
  • Horizontal Datum - World Geodetic System (WGS 84)
  • Vertical Datum - shoreline based on Mean High Water (MHW)
  • The WVS coastline data is available on NGDC's "Global Relief" CD-ROM, along with the now-ancient WDBII political bounds and rivers.

Note: The version of WVS used in the coastline extractor does not include all the features (such as lakes, rivers,bradwaters,glaciers, international boundaries, country names, etc.) that DMA has in their data set.

Here's some info about the original data, which explains why central america yields duplicates:

SUMMARY: The World Vector Shoreline (WVS) is a digital data file at a nominal scale of 1:250000, containing the shorelines, international boundaries and country names of the world. The World Vector Shoreline is a standard US Defense Mapping Agency (DMA) product that has been designed for use in many applications. The WVS is divided into ten ocean basin area files. Together the ten files form a seamless world, with the exception of Central America, where there is an overlap between the Western North Atlantic file and the Eastern North Pacific File.

The main source material for the WVS was the DMA's Digital Landmass Blanking (DLMB) data which was derived primarily from the Joint Operations Graphics and coastal nautical charts produced by DMA. The DLMB data consists of a land/water flag file on a 3 by 3 arc-second interval grid. This raster data set was converted into vector form to create the WVS. For areas of the world not covered by the DLMB data (e.g. the Arctic and Antarctic), the shoreline was taken from the best available hard copy sources at a preferred scale of 1:250000. The WVS data are stored in chain-node format, and include tags to indicate the landside/waterside of the shoreline.

Purpose: Mission planning and various other computer display command and control systems.

Spatial Reference: Horizontal Datum - World Geodetic System (WGS 84)

Tidal Datum: Mean High Water (MHW)

Data Format: The World Vector Shoreline is available through the Coastline Extractor as an ASCII flat file with longitude and latitude values in decimal degrees (available in MATGEN, MATLAB, or Arc Ungenerate format). The Arc Ungenerate format works with Arc/Info but must be first converted to a shapefile format before it can be used in ArcView.7

Seamless: Yes (with the exception of Central America, where there is an overlap between the Western North Atlantic file and the Eastern North Pacific file).

Potential Applications: Digital databases to support geographic information systems at both regional and global scales.

Process Description: The DLMB data consists of a land/water flag file on a 3-by-3 arc-second interval grid. This raster data set was converted into vector form to create the WVS. For areas of the world not covered by the DLMB data (e.g., the Arctic and Antarctic), the shoreline was taken from the best available hard copy sources at a preferred scale of 1:250,000.6

REFERENCE: E.A. Soluri and V.A. Woodson 1990 World Vector Shoreline. International Hydrographic Review, LXVII(1)

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