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Great Lakes CoastWatch Land Masks and Shoreline Data Files

Data files have names of form "CWGLRRTT.EXT", where:

EXT is the extension:


              GFX = Graphics data file in IDIDAS ANALYZE .GFX format, using
                    compression type B.

              BYT = Graphics data file in byte stream format




RR is the CoastWatch Great Lakes Region subscene covered by the file:


              EO = Lakes Erie/Ontario scene

              MH = Lakes Michigan/Huron scene

              SU = Lake Superior scene

              SY = Great Lakes scene
              


TT is the type of data contained in the file:
      
              CL = coastline data

              LM = land mask data

              RD = land mask with lake regions defined by pixel value,
                   as follows:
                   
                (1) image size 512x512
                   Pixel
                   Value   Geographic Area 
                   -----   ---------------

                     00    Lake Superior
                     01    Thunder Bay
                     02    Black Bay
                     03    Nipigon Bay

                     10    Lake Michigan
                     11    Green Bay
                     12    Grand Traverse Bay

                     20    Lake Huron
                     21    Georgian Bay 
                     22    North Channel
                     23    Saginaw Bay

                     30    Lake St. Clair

                     40    Lake Erie

                     50    Lake Ontario

                    100    Lake Nipigon
                    101    Lake Winnebago
                    102    Lake Simcoe
                    103    Lake Wanapitei
                    104    Lake Nipissing

                    255    Land

                (2) image size 1024x1024
                   Pixel
                   Value   Description of Defined Region
                   -----   -----------------------------

                    00     Lake Superior
                    01     Thunder Bay
                    02     Black Bay
                    03     Nipigon Bay
                    04     Western Lake Superior
                    05     Eastern Lake Superior
                    06     Whitefish Bay
                    07     St Marys River North

                    10     Lake Michigan
                    11     Green Bay
                    12     Grand Traverse Bay
                    13     Northern Lake Michigan
                    14     Southern Lake Michigan

                    20     Lake Huron
                    21     Georgian Bay
                    22     North Channel
                    23     Saginaw Bay
                    24     Northern Lake Huron
                    25     Southern Lake Huron
                    26     St Marys River South

                    30     Lake St. Clair
                    31     Detroit River North

                    40     Lake Erie
                    41     Western Lake Erie
                    42     Central Lake Erie
                    43     Eastern Lake Erie
                    44     Detroit River South

                    50     Lake Ontario
                    51     Western Lake Ontario
                    52     Eastern Lake Ontario

                    255     Land