looks like your getting the hang of it.
I have found this excellent matlab google earth toolbox. Just download and extract it, then add the toolbox to Matlab using the addpath command, for me it was addpath(‘C:\Users\Peter\Documents\MATLAB\googleearth’)
Then you can plot direct to kml files. This is the voltage as altitude.
That was abit boring so i also did the speed.
Looks like there is loads you can do with this toolbox, things like surface plots, contor plots and heat maps should be fairly straight forward. We can change the line colors and thicknesses, export loads of plots into a single kml ect. I have only had a short time to play this evening but we should be able to work out more complex stuff.
For this example I have offset the data to be plotted in the z axis(the altitude) such that the minimum value is zero and the maximum is 250 meters. Other wise the change in the value is hard to see.
I have uploaded the two kml files, the .mat file from your log and the updated matlab code here.