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Referring to the following post Calculate velocity x and y components from Lat,Lon and Time

Given the two points with Latitude, Longitude, Height and time

P0 = (Lat0,Lon0, h0, time0)

and

P1 = (Lat1,Lon1, h1, time1)

how can we calculate the velocities in X, Y and Z-directions?

ravindraji4
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1 Answers1

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The best way to go would be to find the Earth-centered XYZ coordinates of your 2 points with these formulas, then rotate them to find the ENU coordinates (East, North, Up, corresponding to your local XYZ system) with this rotation matrix (P0 can be the local reference point for the East-North-Up directions). Finally, divide your coordinates by (Time1 - Time0) to take into account the time component.

FSimardGIS
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  • It worked.. I am writing again regarding the doubt. In case of a third point. P2 = (Lat2,Lon2, h2, time2)

    We can calculate the ENU coordinates w.r.t the first point. Say, East component is xEast = [xEast1;xEast2] and the time vector [time0;time1;time2]. So the Vx1, Vx2 would be Vx1 = xEast1/ time1-time0 and Vx2 = xEast2/time2-time1?? OR Vx1 = xEast1/ time1-time0 and Vx2 = xEast2/time2-time0??

     – ravindraji4 May 17 '18 at 12:02
  • If you wish to calculate the vector from P0 to P2, then it will be (x2-x0) / (time2-time0), etc. If you need each vector individually, it is (x1-x0) / (time1-time0)... for Vector 1, and (x2-x1) / (time2-time1) for Vector 2 – FSimardGIS May 17 '18 at 16:08