Metadata for Great Lakes Shoreline files (x-y columns)
G. Lang
gregory.lang@noaa.gov


Original data at:
http://www.glerl.noaa.gov/data/bathy/bathy.html
http://www.glerl.noaa.gov/ftp/publications/tech_reports/glerl-016/dr-016.html

The shorelines of the Great Lakes and many of the islands were digitized from National Ocean Survey 1:400,000 charts 
for Lakes Ontario (chart number 14800), Erie (chart number 14820), St. Clair (chart number 14820); 1:500,000 charts 
for Lakes Huron (chart number 14860) and Michigan (chart number 14900); and the 1:600,000 chart for Lake Superior 
(chart number 14960) on a digitizing table. The average segment length was 1.24 km. The geographical coordinates of 
the endpoints of each segment were then ordered so that each lake shoreline and each island formed a closed loop. The 
Straits of Mackinac were closed to separate Lakes Michigan and Huron.


The original shoreline data files (*.dat) contain longitude/latitude pairs arranged in sets of 4 pairs. Fortran format="4(2F9.5)".

These shoreline data files (*.dat2) contain the same longitude/latitude pairs and a dummy depth (0) listed in columns. Fortran format="f10.5,1x,f10.5,i2".


File Format:
1) Each file contains a header, which is the name of the original shoreline data file, followed by
2) The number of closed polygons, followed by 
3) The polygons data,

Each polygon is listed using this Polygon Format:
3a) polygon number, number of points in the polygon, polygon name, followed by
3b) polygon longitude/latitude pair, dummy depth (0).

Note1, the first and last point of each polygon is identical.

Note2, greatlakes.shoreline.dat was created by appending superior.shoreline.dat, michigan.shoreline.dat, huron.shoreline.dat, stclair.shoreline.dat, 
erie.shoreline.dat, ontario.shoreline.dat, and rivers.shoreline.dat.

Note3, mich-huron.shoreline.dat2 was created by appending michigan.shoreline.dat, huron.shoreline.dat, and rivers.shoreline.dat (edited to include 
appropriate rivers, islands).

Note4, erie-stclair.shoreline.dat was created by appending erie.shoreline.dat, stclair.shoreline.dat, and rivers.shoreline.dat (edited to include 
appropriate rivers, islands).