function c=depths(z)

depths= 1.e-3*[0.    150.    300.    450.    600.    750.    900.    1050.  1200. ...  
    1500.    1800.    2100.    2400.    2700.    3000. 3300.    3600. ];

speeds= [ 1.537    1.523    1.509    1.490    1.484    1.482    1.483  1.484 ...   
    1.486    1.486    1.489    1.495    1.499    1.503 1.508    1.515    1.521 ];

d=splin(depths, speeds); c= interp(z, depths, speeds, d);

endfunction


function cp=depthsp(z)

depths= 1e-3*[0.    150.    300.    450.    600.    750.    900.    1050.  1200. ...  
    1500.    1800.    2100.    2400.    2700.    3000. 3300.    3600. ];

speeds= [ 1.537    1.523    1.509    1.490    1.484    1.482    1.483  1.484 ...   
    1.486    1.486    1.489    1.495    1.499  1.503   1.508    1.515    1.521 ];


d=splin(depths, speeds); [c, cp]= interp(z, depths, speeds, d);

endfunction