How to compare driven lines?

[Crosseinsteiger]

Dear Racers,

I am using this laptimer in Motocross.
It would help me, to compare two different lines with each other.

For example, there are two lines in a corner.
A outside and a inside line.
I can set a split time for this corner.
Then I do several laps.
I can see the split times, but I can not see which line I took.
A overlay of the reference lap with the choosen lap would help.

Is there a possibility to overlay two laps on the Ipad?

Thank you and ride safe!

Christoph

[Harry]

The only solution currently provided is an export of both lap and reference lap to .kml or .vbo for side by side comparison using a desktop computer. LapTimer v18 will add a feature to show lap and reference lap side by side - most probably including a synchronized animation of cars driving this lines.

- Harry

[Crosseinsteiger]

@ Harry:
Thank you for your answer!
Christoph

[gplracerx]

Of course that presumes your GPS data are precise enough to distinguish between lines. I've only seen an obvious difference between Indy cars and Formula Atlantics on an oval track. The Indy cars were doing a diamond in the corner, slowing down a lot and turning very tightly at an apex near the outside edge of the track, while the Atlantics were taking the momentum preserving line of nearly constant radius with the apex well inside the Indy car apex.

[Harry]

Yes, that's indeed difficult to compare and to recognize. To understand the impact of a line driven you need a) be able to recognize the line (i.e. very good accuracy and appropriate update rate) and b) drive the corner at the limit. In case both items are met, you can recognize a good line watching the gap graph, or by comparing the max speed achieved behind the corner (depends on corner / straight combination). I wrote "synced animation" above. This means one can set any point as the start of comparison and two cars are positioned exactly at that position (shifted to left or right so they match lap and reference lap respectively). Now, one can start an animation showing the two cars, an advantage will become obvious very fast. That is at least the sketch for this feature I have in mind currently.

- Harry

[gplracerx]

Corner exit speed, assuming the corner exits onto a straight is a classic measure. But there is almost as much time to be gained on corner entry as on corner exit, assuming that the corner is at the end of a straight. So the total time spent in the corner is also a useful measure. I used to measure that at a corner on a hill climb course (the house turn at Chimney Rock Park). The correlation between time spent in that corner and time for the whole course was quite good. The most important corner is the one with the highest exit speed, not necessarily the one leading onto the longest straight. The variation in exit speed on fast corners between different drivers tends to be higher than for slow corners.