[R-sig-Geo] Integrating a trajectory

[MacQueen, Don]

In two dimensions, interp() from the akima package would be a good
starting point. You might have to first generate a set of suitably spaced
lon,lat coordinates along the trajectory, depending on how the trajectory
is stored.

In the absence of something already existing for your 3d situation, I
suppose it could be done by first interpolating in 2d at altitudes above
and below the trajectory, then doing vertical interpolation between them.
I doubt that would be the most accurate interpolation, but it might be
good enough.

If you go to CRAN task view "CRAN Task View: Handling and Analyzing
Spatio-Temporal Data", there is a whole section "Moving objects,
Trajectories".

-Don

-- 
Don MacQueen

Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062





On 2/26/15, 5:50 AM, "Paul Woods" <p.woods at qub.ac.uk> wrote:

>Hi everyone,
>
>Perhaps this is a little removed from strict geography, but you seem to
>be a clever bunch.
>
>I¹m looking for a method in R or Python to integrate along a trajectory,
>through a regular grid. So, imagine an aeroplane flying from London to
>New YorkŠ I want to calculate how much material in the atmosphere the
>aeroplane comes into contact with. I have a regular grid with the density
>of the atmosphere at each lon, lat, altitude grid point, but of course
>the plane does not travel along grid lines, so some interpolation would
>be needed. Any ideas on where to start in calculating how much atmosphere
>a plane would scoop up from London to New York?
>
>Thanks,
>
>Paul.
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