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Coastline Extractor

Geographic Range of Coastline to Extract
(decimal degrees, west and south are negative)

upper latitude
westernmost longitude
easternmost longitude
lower latitude

Note: Please enter the geographic range first, then choose criteria below.
Please do not try to extract huge regions like all of the US coastline from WVS, there is a 500,000 point limit on each extraction. Thanks! If you select a range that covers more than a few degrees, be prepared to wait while the data are extracted and (optionally) the coastline image is created.

Coastline database:

Compression method for extracted ASCII data:
None GNU GZIP UNIX Compressed ZIP

Coast Format options:
Mapgen Arc/Info Ungenerate Matlab Splus

Coast Preview options:
No preview GMT Plot

Extract the Coast:

Note: If you preview the coast, please wait for it to be generated! If you abort and reload the form, you will just create another process that will slow things down even more!

The Coastline Extractor was created by Rich Signell of the U.S. Geological Survey / Geologic Division / Coastal and Marine Program / Woods Hole Field Center. The extractor pages are currently hosted by the NOAA/National Geophysical Data Center, Marine Geology and Geophysics Division.

The electronic form above allows you to extract coastline segments bounded by a specified latitude/longitude range. Plots the coast you extracted also!

The selected data returned by the query is an ASCII flat file with two columns containing longitude and latitude in decimal degrees (west negative). The default MAPGEN format is lon,lat with new segments separated by a line containing the characters "# -b". The MATLAB format is the same, but with the characters "nan nan" indicating line breaks, so in MATLAB you can type "load coast.dat" then "plot(coast(:,1),coast(:,2)". The Arc Ungenerate format works with Arc/Info.

ArcView will not read the Ungenerate format directly, but you can convert from Ungenerate to a Shape file that ArcView can read using the script gen2shap1.ave. For MAPINFO users, there is a tool CoastCon.zip from Peter Lyngs that converts the MAPGEN format output to MapInfo Import Files (MIF).

The ASCII files may be compressed in a variety of formats before downloading.

The default values below will give you the WVS coastline for Cape Cod, Marthas Vineyard and Nantucket in Massachusetts, USA.

About the data sets:
  • World Coastlines and Lakes. Crude. World Wide Coverage. This data is suitable for map scales of 5,000,000 or smaller.

  • World Data Bank II. Fair Resolution. World Wide Coverage. This data is suitable for map scales of 2,000,000 or smaller. Also contains international and internal political boundaries and rivers.

  • World Vector Shoreline. Better Resolution. World Wide Coverage. This data is suitable for map scales of 1:250,000 or smaller.

  • NOAA/NOS Medium Resolution Digital Vector Shoreline. Best Resolution. United States Coverage, digitized from NOAA nautical charts. This data is suitable for map scales of 1:70,000 or smaller. Note: There may be a few odd data points in this version of the data set (September, 1994). If you see something strange, you might want to check the official source of this data at the official NOAA medium resolution coastline web site.

Our processing details may be found here.

Note: If you are interested in making the coastline continuous and you have Matlab, click here.

Related Links

pages maintained for Rich Signell by: NOAA/NGDC Marine Geology and Geophysics Division