Interpolating LatLng-Data

Hi,

I am currently building a small application that visualizes LatLng-Paths over time. Basically, what I have are lists of WSG84-LatLng-coordinates, all of them with a timestamp. The application should display them moving over time, so I have to interpolate the position between LatLng with time A and LatLng with time C at time B. I have millions of these paths and the position has to be calculated in real-time, so efficiency matters. This is all standard stuff, if you are in a cartesian x,y-system, and at the moment, I am treating the LatLng-coordinates as cartesian and do a simple linear interpolation.

However, I am aware that LatLng-coordinates are not cartesian coordinates and that linear interpolation can be problematic on the larger scale because the earth is, of course, not a plane. I dont expect to run into any problems here because the distance between two coordinates at the moment is (at the most!) one kilometer, but I want the “get it right” at this stage of the development process, which means: i want the app to be able to interpolate correctly on a larger scale.

Now, my idea is to project the whole dataset to the plane using spherical mercator projection and to do the interpolations on this x,y-plane. Is this a reasonable approach? Do I win anything doing it that way?

thank you,
sprungfeld

Well, if no more answer comes up here to your question that seesm not really be related directly to OSM, try to search or ask at http://gis.stackexchange.com …?