When Wesley Hill was scoring the Worlds last night he was
confronted with Scott Barrett's track log that looked exactly like this although
at that time he also was displaying Christian Ciech's track log in addition to
Scott's:

First, he had been told by Scott that he beat Christian into the goal (which has
been confirmed). Second, he has downloaded Scott's Garmin GPS because Scott's
vario went out on him half way through the flight (pretty amazing that Scott won
the day flying without a vario).

Third, it was extremely difficult to believe that at 17:59:03 Scott turned
directly 90 degrees at very high speed to his course line and thirty second
later was heading away from the goal. That did not "look" right.

Fourth, a track log that had been recording at one or two second intervals was
now displaying to adjacent track log points at thirty seconds apart.

We assumed that there were issues with the Garmin correctly recording Scott's
position likely due to his body covering the Garmin up as he pulled in hard and
raced to goal.  But is seemed very unlikely that he was going 600 to 1800
kmh as GPS Dump was calculating.

The FS program scored Scott based in its calculation of when he crossed the
circumference of the 400 meter goal cylinder, but we doubted the validity of the
calculation given the odd looking track log data displayed by FS.

Wesley was clear that track log data points that he could see in the track log
file in GPSDump were not being displayed by FS. He attempted to delete some
points to get FS to recalculate the goal cylinder entry time. That helped but it
was still not the best solution and it looked like he would have to calculate
the goal cylinder crossing time manually.

I asked him to create an IGC file from Scott's KML track log file and display it
in SeeYou. Here's what we got:

Obviously Scott's Garmin GPS lost track of where he was for an interval.

Zooming in a bit closer at the goal:

The Garmin GPS was recording position fine until, at 17:58:10 at 2.55 km from
the edge of the start cylinder with Scott flying at 70 mph, the recorded track
log started jiggling. Estimated speeds at that point turned to about 250 mph as
his actual location was no longer being properly recorded.

We saw right away that FS was not correctly displaying the track log data and no
longer believed the calculation for his goal cylinder crossing time.

I left at that point with Wesley ready to deal with the data and come up with
the best estimate possible from the actual data, given that the data was bad but
the best that we had.

The first data point from the track log inside the goal cylinder was 17:59:38.
That is what Wesley has used as Scott's goal cylinder circumference crossing
time, although obviously he would have crossed before that and Christian has
stated that Scott made goal before him.

Today I took Scott's original KML track log file and the IGC file made from it
and decided to try to figure out why FS had apparently lead us astray. It turned
out to be a very simple answer.

Check out the last item in this FS dialog box:

Indeed FS had "filtered" out track log points that didn't "look" right. It
appeared to Wesley and I to also make an interpolation of Scott's goal cylinder
crossing time that was incorrect from these filtered track log points.

Once I unchecked this last check box and reopened the FS display of the track
log, I got the same picture as SeeYou displayed of Scott tracklog.

I then went one step further. I decided to see if I could use the last
apparently good track log data point, Scott's airspeed at the point, and the
distance to goal, and assuming that he kept that air speed and knowing from
Christian that Scott had indeed beat him to goal come up with a "better"
calculation of his goal cylinder crossing time.

Assuming that he is flying at 112.7 km/h (70 mph) and he has to go 2.55 km, he
is able to do that in 1 minute and 21.46 seconds so that his goal cylinder
crossing time would be 17:59:31 (6 seconds less than Wesley's use of the value
shown on Scott's track log). If he in fact (and most likely) flew even faster
(as he beat Christian's time of 17:59:26) at 80 mph he would have had a 17:59:21
crossing time.

The points difference between Scott and Christian (4th and 1st place) was 21
points out of 968. Wesley chose the most conservative value for Scott's goal
cylinder crossing time (a data point inside the goal cylinder). Using an
interpolation from the data (bad as it is) would have put the crossing time at
17:59:36 (approximately). This calculation seems to be to be valid, while mine
is speculative (although witness based).

I would argue that Scott deserves few more points with a "better" calculation.

I then went yet another step further. I looked at the section of the track log
that was displaced to the south. This is it:

An analysis of this section shows that Scott was traveling at 75 to 77 mph
directly toward the goal for .9 km (ignoring the displacement) with the bottom
track log point at 17:59:33. It apparently took five seconds for the Garmin GPS
to properly record the correct location.

Software is not perfect and human beings are still required to evaluate the
results of the calculations as well as the recordings of the instruments.