MATLAB Examples

antbounds_data documentation

The antbounds_data function returns the coordinates of line data in the MEaSURES Antarctic Boundaries for IPY 2007-2009 from Satellite Radar dataset Version 2.

The dataset is described on the NSIDC site here: http://nsidc.org/data/NSIDC-0709

Contents

Syntax

[lat,lon] = antbounds_data(datatype)
[x,y] = antbounds_data(datatype,'xy')
[...,names] = antbounds_data('shelves')

Description

[lat,lon] = antbounds_data(datatype) returns the geo coordinates (lat,lon) of any of the following datatypes:

  • 'coast' seaward limit of the ice sheet
  • 'gl' landward limit of flexure detected by InSAR
  • 'shelves' a cell array of all ice 180 ice shelves in the dataset
  • 'shelfname' any of the shelf names in the dataset, must be exactly one of the following:
      'Abbot'                 'Getz 1'               'Porter'
      'Abbot 1'               'Getz 2'               'PourquoiPas'
      'Abbot 2'               'Gillet'               'Prince Harald'
      'Abbot 3'               'Hamilton'             'Publications'
      'Abbot 4'               'Hamilton Piedmont'    'Quar'
      'Abbot 5'               'Hannan'               'Quatermain Point'
      'Abbot 6'               'HarbordGlacier'       'Rayner Thyer'
      'Ainsworth'             'Harmon Bay'           'Rennick'
      'Alison'                'Hayes Coats Coast'    'Richter'
      'Amery'                 'Helen'                'Riiser-Larsen'
      'Andreyev'              'Holmes'               'Ronne'
      'Arneb'                 'Holt'                 'Rose Point'
      'Astrolabe'             'HornBluff'            'Ross East'
      'Atka'                  'Hoseason'             'Ross West'
      'Aviator'               'Hovde'                'Rund Bay'
      'Bach'                  'Hull'                 'Rydberg Peninsula 1'
      'Barber'                'Hummer Point'         'Rydberg Peninsula 2'
      'Baudouin'              'Ironside'             'Sandford'
      'Borchgrevink'          'Jackson'              'Shackleton'
      'Brahms'                'Jelbart'              'Shirase'
      'Britten'               'Kirkby'               'Skallen'
      'Brunt Stancomb'        'Land'                 'Slava'
      'Campbell'              'LarsenA'              'SmithInlet'
      'CapeWashington'        'LarsenB'              'Sorsdal'
      'Cheetham'              'LarsenC'              'Stange'
      'Chugunov'              'LarsenD'              'Sulzberger'
      'Cirque Fjord'          'LarsenD 1'            'Suter'
      'ClarkeBay'             'LarsenE'              'Suvorov'
      'Commandant Charcot'    'LarsenF'              'Swinburne'
      'Conger Glenzer'        'LarsenG'              'Telen'
      'Cook'                  'Lauritzen'            'Thomson'
      'Cosgrove'              'Lazarev'              'Thwaites'
      'Crosson'               'Lillie'               'Tinker'
      'Dalk'                  'Liotard'              'Totten'
      'Dawson Lambton'        'Mandible Cirque'      'Tracy Tremenchus'
      'Deakin'                'Manhaul'              'Tucker'
      'Dennistoun'            'Marin'                'Underwood'
      'Dibble'                'Mariner'              'Utsikkar'
      'Dotson'                'Marret'               'Venable'
      'Drury'                 'Matusevitch'          'Verdi'
      'Drygalski'             'May Glacier'          'Vigrid'
      'Edward VIII'           'McLeod'               'Vincennes Bay'
      'Ekstrom'               'Mendelssohn'          'Voyeykov'
      'Eltanin Bay'           'Mertz'                'Walgreen Coast 1'
      'Erebus'                'Morse'                'Walgreen Coast 2'
      'Falkner'               'Moscow University'    'WattBay'
      'Ferrigno'              'Moubray'              'West'
      'Filchner'              'Mulebreen'            'Whittle'
      'Fimbul'                'Myers'                'Wilkins'
      'Fisher'                'Nansen'               'Williamson'
      'Fitzgerald'            'Nickerson'            'WilmaRobertDowner'
      'Flatnes'               'Ninnis'               'Withrow'
      'Fox'                   'Nivl'                 'Wordie (Airy Rotz Seller)'
      'Francais'              'Noll'                 'Wordie (Cape Jeremy)'
      'Frost'                 'Nordenskjold'         'Wordie (Harriott)'
      'Gannutz'               'Parker'               'Wordie (Harriott Headland)'
      'Garfield'              'Paternostro'          'Wordie (Prospect)'
      'GeikieInlet'           'Perkins'              'Wylde'
      'George VI'             'Philbin Inlet'        'Zelee'
      'Getz'                  'Pine Island'          'Zubchatyy'

[x,y] = antbounds_data(datatype,'xy') returns polar stereographic (true lat 71 S) coordinates in meters.

[...,names] = antbounds_data('shelves') also returns an array of ice shelf names.

Example 1: Load and plot grounding lines and coastlines

Load and plot a continent's worth of coast line data. Plot the whole ice sheet as a blue patch object.

[lat,lon] = antbounds_data('coast');
patchps(lat,lon,'blue')

And overlaying a red grounding line is just as easy:

[gllat,gllon] = antbounds_data('gl');
plotps(gllat,gllon,'red')

Example 2: Mask data corresponding to a specific ice shelf

Consider a 10 km resolution grid, 700 km wide, centered on Wilkins Ice Shelf. We can use psgrid to create such a grid:

[xgrid,ygrid] = psgrid('wilkins ice shelf',700,10,'xy');

That grid looks like this:

plot(xgrid,ygrid,'.','color',[.5 .5 .5])
axis image
hold on

That doesn't tell us much, so let's put it into context of some grounding lines and coastlines. Make them all black:

antbounds('gl','k')
antbounds('coast','k')
antbounds('shelves','k')
scalebarps

If you want to find all your grid points that correspond to any ice shelf, the best tool for that is the isiceshelf function. Let's identify ALL ice shelf grid points as black x marks:

shelf = isiceshelf(xgrid,ygrid);
plot(xgrid(shelf),ygrid(shelf),'kx')

But what if you're only interested in Wilkins Ice Shelf? The easiest way to determine which grid points are within the Wilkins Ice Shelf polygon is to load the outline of Wilkins Ice Shelf via antbounds_data, then use the Matlab function inpolygon to determine which points are inside the Wilkins outline. Start by loading the polygon and plot it as a thick red line:

[wx,wy] = antbounds_data('wilkins','xy');
plot(wx,wy,'r','linewidth',2)

Now determine which grid points are inside the Wilkins outline and plot thos grid points as red circles:

wilkins = inpolygon(xgrid,ygrid,wx,wy);
plot(xgrid(wilkins),ygrid(wilkins),'ro')

Now label the ice shelves and use mapzoomps to place an inset map in the upper right hand ('ne') corner. Below I'm using my rgb function to automatically give the RGB values of dark blue

labelshelves('fontweight','bold','fontsize',20,'color',rgb('dark blue'))
mapzoomps('ne')

Citing this dataset

If you use this dataset, please cite the following:

  • The dataset: Mouginot, J., B. Scheuchl, and E. Rignot. 2017. MEaSUREs Antarctic Boundaries for IPY 2007-2009 from Satellite Radar, Version 2. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. http://dx.doi.org/10.5067/AXE4121732AD.

Author Info

This function and supporting documentation were written by Chad A. Greene of the University of Texas Institute for Geophysics (UTIG), November 2016. Updated May 2017.