The American Surveyor

NOAA Coastline Extractor

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Are you searching for a useful tool that will provide you with coastal boundaries for anywhere in the World? Search no more.

(A GISuser feature) – Are you searching for a useful tool that will provide you with coastal boundaries for anywhere in the World? Search no more… the NIMA Coastline Extractor tool is what you need. I recall using this product about 5 years agao and to this day its still one of the most valuable free data products around. Essentially, users have access to several coastline vector databases, ranging in scale from 1:250k to 1:5 million. Using the dialogs provided, users enter coordinates of a bounding rectangle (ie. Min and Max lat/long values. Then, select a coastline database, a compression method (None, GNU, UNIX, ZIP), and a spatial data format (Mapgen, Arc/Info Ungenerate, Matlab, Splus). See figure 1 below for a sample of the GUI

Fig 1: User input screen

All variables must be addressed. Once the user accuractely enters in the required information a preview of the output data product is presented (see figure 2).

Fig 2: Preview desired coastline

The extracted coastline is first presented in a preview screen before users are committed to download. Once the user is satisfied with the data, a .zip file is made available. Simply click on the file name (hyperlink) to commence downloading data. Another cool way to preview or define your data is the Java mapper. A nifty java applet lets users simply draw a rectangle around a desired region to preview and select a dataset (see figure 3).

Fig 3: Java Mapper preview

Data may not be readily usable by all GIS software programs, however, a couple of useful utilites are referenced which may be of use. ArcView will not read the Ungenerate format directly, but users can convert from Ungenerate to a Shape file that ArcView can read using the script gen2shap1.ave. For MAPINFO users, the site recommends a tool CoastCon.zip from Peter Lyngs that converts the MAPGEN format output to MapInfo Import Files (MIF).

Please note, this fine resource was developed by Rich Signell and is hosted by NOAA

Some useful facts about the data:

  • World Coastlines and Lakes – This data is suitable for map scales of 5,000,000 or smaller. (Global coverage)
  • World Data Bank II – This data is suitable for map scales of 2,000,000 or smaller. Also contains international and internal political boundaries and rivers. (Global coverage)
  • World Vector Shoreline – This data is suitable for map scales of 1:250,000 or smaller. (Global coverage)
  • NOAA/NOS Medium Resolution Digital Vector Shoreline. Best Resolution. 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. (US coverage)

Related weblinks:

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