[GraphHopper] Waypoints and Deviation detection

[David Ssali]

Greetings...
I have been scratching my head on two issues
1) How to get a route via a certain point. Say i need to move from point 
A to C via B.I know the obvious  thing is to get the route from A to B 
then B to C but i wonder if there's a direct way to do this using 
Graphhopper.

2) How to detect a deviation.
I came up with an algorithm where if the Heading or bearing is different 
from the heading to the next point on the route, then i assume there's a 
deviation...of course putting in a degree of error. But the challenge is 
that sometimes there may be a sharp corner which causes the car to point 
in the "wrong" heading yet it is actually still on the correct path.
Is this something that Graphhopper has already dealt with? If not, could 
someone help me with a better algorithm to handle it?

Regards,

-- 
David Ssali
Team Leader
EYGO LIMITED
P.O. BOX 22214, KAMPALA
Tel: +256 41 469 1531
Mob: +256713178532