Single flat file
The data format that def can read

Simple flat files are handled easily by the def method.

# Basic Hydrographic Data
# from Carl Wunsch
#

sta, lat,    lon,    press,   temp,   sal,     o2,    sigth 
 6   38.03  -72.99    5.000  16.942  33.097   6.020  24.069
 6   38.03  -72.99   25.000  14.871  34.715   6.380  25.782
 6   38.03  -72.99   49.000  10.605  34.557   5.820  26.503
 7   37.93  -72.69    5.000  17.697  33.787   5.760  24.419
 7   37.93  -72.69   25.000  15.268  35.001   6.320  25.915
 7   37.93  -72.69   49.000  14.548  35.298   5.620  26.302
 7   37.93  -72.69   99.000  12.162  35.426   4.710  26.892
 7   37.93  -72.69       nd  12.229  35.592      nd  27.010
 7   37.93  -72.69  199.000  11.027  35.416   4.440  27.100
 7   37.93  -72.69  300.000   8.478  35.119   3.600  27.300
 ... (and so on) ...