| Particle_Trace question ? [message #59410] |
Tue, 18 March 2008 15:56 |
millward.george
Messages: 2
Registered: March 2008
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Junior Member |
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Hi there,
I am trying to use particle_trace to create streamlines from a vector
field - but I'm having quite alot of trouble
understanding the documentation.
I have a velocity field which is a longitude,latitude array of
Southward and Eastward velocities.
My arrays are 20 longitudes by 91 latitudes. So my 2 arrays are:
V_south(20,91) and V_east(20,91)
I now want to feed these into Particle_trace.
The syntax for Particle_trace requires a single array (which they call
Data) of
size Data[2,dx,dy]
I'm assuming that dx and dy are the indexes for longitude and latitude
and the first dimension (2)
is for the 2 components of the field, so:
data(0,lon,lat) = V_east(lon,lat)
data(1,lon,lat) = 0.0 - V_south(lon,lat)
Nowhere in the documentation does it define the directions - is dx
Eastwards - is dy Northwards? Very confusing !!
And the seed points - are these longitude, latitude points or
something ? Again, no real explanation in the documentation.
....or have I got it completely wrong ?
Any help with this very much appreciated
Cheers,
George.
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