Coastal & Marine Geology InfoBank

Home FACS Activities Atlas Geology School Related Sites More

USGS InfoBank program -- swath

Skip navigational links
Loading
InfoBank Programs: by Name   by Topic  
Expanded Description
Topic Description
Name
swath
Synopsis
/infobank/programs/bat/swath/swath.for
Description
  Program to convert extract multibeam data for an area.

       
PROMPTS
  ' Enter a latitude limit:'

  ' Enter the other latitude limit:'
  ' Enter a longitude limit:'
  ' Enter the other longitude limit:'
  ' Enter an output file name:'
    
INPUT
  For the user -- only the lat/long window limits.

  For the program -- data maintained in /infobank/swath is accessed.
    
OUTPUT
  file of time/lat/long/depth/ping#

    
RELATED_PROGRAMS
  SWATHLIST  --  generates a list of data set names and coverage areas 

                     of files currently in pmgswath
  SEABEAM      --  extracts Seabeam bathymetric data
  SEABEAMLIST  --  generates a list of data set names and coverage areas
                     of files currently in pmgseabeam
  DEM          --  extracts DEM topographic data
  DEMLIST      --  generates a list of data set names and coverage areas
                     of files currently in pmgdem
    
BACKGROUND
  Multibeam Full Resolution data sets are disseminated by NOAA/NOS as 

  EEZ Bathymetric Data.  
       
  Data were collected as multibeam swath soundings for depths greater
  than 100 meters and up to 200 nautical miles from U.S. coastlines
  (EEZ limits).  Only some areas have coverage.
   
  The data sets are produced for time periods of surveys (cruises).
   
  Original data are typically collected with tracklines run generally
  parallel to known contours.  The swath is perpendicular to the
  trackline of the platform.  At least 10% sidelap is maintained.
  Swath width is about 70% of the water depth for depths greater
  than 600 meters.  For shallow water, the swath width is up to
  250% of the water depth.
   
  Data are disseminated on 6250bpi, 9-track, VMS-labeled tapes.
  DAPS maintains online on ISDMNL a complete set of the highest
  resolution of these data.  Access is via:    "swath"
   
  Typically, there are 5 to 10 million soundings for each area.  
  The data has a horizontal accuracy of 50 meters and +/- 1% error 
  in depth.
   
  For a more complete description see:
        README.DOC FILE
        Documentation for Dissemination of NOAA/NOS Gridded EEZ
          Bathymetric Data, January 1991
        (Clint Steele, x3170 has a copy)
      
   Format for magnetic tape records of multibeam data
              University of Rhode Island
         format from NOAA as of February, 1992
   9 track
   6250 bpi
   256 words (values) (512 bytes) (integer * 2) per record
   5 logical records of 51 values per physical record
     
   logical record description
   word    description
 sea beam data
   1-19   19 depths from sea beam (meters - 1500 m/sec. velocity)
            1  (port-most), 10 (center), 19 (starboard-most)
            value of 0 = no data
   20-38  19 cross track distances (meters)
            20 (port-most), 29 (center), 38 (starboard-most)
 other data
   39     platform's speed in knots * 100
   40     platform's course in degrees * 10 (i.e.: 0 thru 3599)
   41     not used
   42     heading from multibeam (caution: 2's compliment)
 positioning    
   43     latitude fractions of minute * 10000
   44     latitude minutes above south pole
   45     longitude fractions of minute * 10000
   46     longitude minutes east of prime meridian (Greenwitch)
 time
   47     seconds
   48     minutes since beginning of day
   49     julian day
   50     year
   51     multibeam time in 1/10 seconds since beginning of hour
                 (caution: 2's compliment)
   
 This sequence is repeated 5 times per physical record (5*51 = 255)
 value 256 is not used
    
SUBROUTINES
  vescinit            (shared DRS external routine) 

  lib$find_file       (VAX/VMS Run-Time routine)    
  forerror            (shared DRS external routine) 
  stringlen           (shared DRS external routine) 
    
FUNCTIONS
  index               (FORTRAN intrinsic function)  

    
AUTHOR
  Clint Steele    2/13/92 based on SEABEAM_LAMONT.FOR and DEM.FOR

  Clint Steele    3/24/92 added expancion of search area by 1km
                          to allow for beam width
  Clint Steele    5/15/92 added output of times
  Clint Steele    9/2/94  added 90 degree change before call to
                          deadreckon
  Clint Steele    11/13/96  Major re-write to accomodate move to SHARK

    
Reads
        read (SummaryUnit, 500, end = 501) Count(NumberFound),
     *        FileNorth (NumberFound), 
     *        FileSouth (NumberFound), 
     *        FileWest  (NumberFound), 
     *        FileEast  (NumberFound), 
     *        FileName  (NumberFound)
          read (InUnit, 335, iostat = ErrorFlag, end = 99)
     *          Time, Latitude, Longitude, OtherLength, Other
Writes
        write (6, 49) LimitNorth, LimitWest, LimitEast, LimitSouth
        write (CompressName, '(100x)')
        write (DataName, '(100x)')
          write (Other, '(80x)')
                    write (90, 101) Time, 
     *              Latitude, Longitude, Other(1:OtherLength)
                         write (6, 475) 
     *                          (int(((OutputCount + TotalOutputCount) /
     *                               (ExpectedCount * 1.0)) * 100.0))
Opens
      open (unit            = SummaryUnit,
     *      file            = SummaryFile,
     *      form            = 'formatted',
     *      iostat          = ErrorFlag,
     *      status          = 'old')
        open (unit       = InUnit,
     *        file       = DataName,
     *        access     = 'sequential',
     *        iostat     = ErrorFlag,
     *        form       = 'formatted',
     *        status     = 'old')
Calls
      call degrees (LimitNorth, LimitSouth, LimitWest, LimitEast)
        call forerror (ErrorFlag)
        call openem (0,-1)
        call stringlen (SearchName, LengthEnd)
        call system ('uncompress -c '//CompressName//
     *         ' > '//DataNa
          call forerror (ErrorFlag)
              call forerror (ErrorFlag)

Skip footer navigational links

Coastal and Marine Science Centers:  Pacific   St. Petersburg   Woods Hole  
InfoBank   Coastal and Marine Geology Program   Geologic Information   Ask-A-Geologist   USGS Disclaimer  


Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://walrus.wr.usgs.gov/infobank/programs/bat/swath/swath.doc.html
Page Contact Information: InfoBank staff
Page Last Modified: Mon Sep 16 03:38:52 PDT 2013  (chd)