LATLON2XYZ is the jSphere module of jLab.

 LATLON2XYZ  Converts latitude and longitude into 3D Cartesian coordinates.
 
    [X,Y,Z]=LATLON2XYZ(LAT,LON) converts latitude and longitude of 
    a position on the surface of a sphere into Cartesian coordinates.  
 
    LAT and LON are in degrees and X, Y, and Z are in kilometers.  
 
    LAT and LON may either be arrays of the same size, or LON may be an
    array and LAT a scalar.  X, Y, and Z will have the same size as LON.
 
    The Cartesian coordinate system is a right-handed system whose
    origin lies at the center of the sphere.  It is oriented with the 
    Z-axis passing through the poles and the X-axis passing through
    the point LAT=0, LON=0.  
 
    By default, the radius of the sphere is taken as RADEARTH.
    LATLON2XYZ(LAT,LON,R) uses a sphere of radius R, in kilometers,
    instead.
 
    LATLON2XYZ is inverted by XYZ2LATLON.
 
    See JSPHERE for related functions.
 
    'latlon2xyz --t' runs a test.
 
    Usage: [x,y,z]=latlon2xyz(lat,lon);
           [x,y,z]=latlon2xyz(lat,lon,R);
    __________________________________________________________________
    This is part of JLAB --- type 'help jlab' for more information
    (C) 2006--2014 J.M. Lilly --- type 'help jlab_license' for details