Downloading ETOPO Bathymetry and Loading it into Matlab

If the code or instructions below are helpful to you, I'd love to hear it. Always nice to know whether it's worthwhile to put these kinds of instructions online. (Send me an e-mail at the address above.) Even better, if you encounter and fix a relevant data-access issue that isn't in the "troubleshooting" below, let me know so I can add it to the page.

ETOPO Bathymetry

How to download, parse into matlab, and plot bathymetry

URL: http://www.ngdc.noaa.gov/mgg/fliers/06mgg01.html

1. DOWNLOAD DATA
1. Click "make custom grids"
2. Create a grid id (I used "faroeice")
   grid database: ETOPO2 2-minute Global Relief Ver 2
   grid area: (55,70)N (-30,0)E == 30W to 0E
   grid cell size: 2-minutes (note, for large geographic regions, might prefer 4 or 10-minute grid size)
   grid format: Choose:
   "XYZ (lon, lat, depth)", "No Header", "Comma" and check "Omit Empty"
   
   SUBMIT


3. Retrieve Individual files
   Find: faroeice_####.xyz
   
   Right click and save to a dedicated directory. (I used ./data/etopo2/)
   
2. PARSE DATA
   
   Use Matlab read_xyz_scr.m which calls read_xyz.m
   
   Update the following variables in the code:
   input_dir (/home/eleanor/data/etopo2/)
   filename (faroeice_####.xyz)
   lat_lim e.g. [56 67]
   lon_lim e.g. [-20 0]
   
   NOTE: WOA and WOD plotting scripts use bathymetry.
   After reading in the data, use a
   >> save FaroesBathy bathy
   where bathy.lat, bathy.lon and bathy.depth are read by read_bathy.m
3. PLOT BATHYMETRY USING MATLAB
   Can use read_bathy.m but set PLOTflag=1


4. PLOT USING GMT
   Use the script faroesbathy.csh with .gmtdefaults4 (optional).

Need something higher resolution? LDEO at Columbia has swath data online. I haven't accessed it yet, but the website is here: http://www.geomapapp.org/.