Re: plotting trajectories

[Ansley Manke <Ansley.B.Manke@xxxxxxxx>]

Hi Michael,
Ferret has no way of knowing which direction to go, except by the
value of the longitudes.  I think you need to use a new variable
definition to put the points you want plotted from west to east on
the
other side of the prime meridian.  Something like this should
do the
trick:

let/units=deg mylon = {340,350,355,360, 12}
let/units=deg mylat =  { 24, 25, 27, 30, 34}

let   mylon_1 = if mylon lt 180 then mylon+360 else mylon

plot/vs/line mylon_1, mylat

Ansley Manke

Michael Traub wrote:

Hi!

I would like to plot air parcel trajectories overlaying a world map.
The positions of of each parcel is given by its longitude and latitude. It is no problem to plot all positions, but it is a problem to combine the positions with a line:

If

                lon_1 = 340°  lat_1 = 24°
                lon_2 = 12°  lat_2 = 24°

ferret plots a line in x-direction from 340° to 12° from EAST to WEST!!!
HOW TO MAKE FERRET PLOTTING LINES FROM WEST TO EAST CROSSING 0°????

Does somebody has an idea?

Michael

--
Ansley Manke  Pacific Marine Environmental Laboratory  Seattle
WA