Great Lakes CoastWatch Land Masks and Shoreline Data Files

  • http://coastwatch.glerl.noaa.gov/ftp/masks/gfx/ Modified [political boundaries REMOVED] versions of graphics data files supplied with IDIDAS v.1.5, which are higher resolution than the shoreline data supplied in CoastWatch image files.
  • http://coastwatch.glerl.noaa.gov/ftp/masks/stream/ Above graphics data files in byte stream format.
  • http://coastwatch.glerl.noaa.gov/ftp/masks/512/IDIDAS/lo_res/ Lower resolution masks embedded in CoastWatch image files.
  • http://coastwatch.glerl.noaa.gov/ftp/masks/depth/ Great Lakes bathymetric data masks.
  • http://coastwatch.glerl.noaa.gov/ftp/masks/1024/cwglsyrd_1024.byt Great Lakes high resolution (1024x1024) mask file (raw data).
  • http://coastwatch.glerl.noaa.gov/ftp/masks/1024/cwglsyrd_1024.asc Great Lakes high resolution (1024x1024) mask file (asc format).
    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