18m here http://wgc2018.onglide.com/current-day.xml?class=18meter

Anyone know how the live tracking speeds are calculated? I see guys flying together with speeds that don't correlate with start times.

Go 70!! Go 5E!! Go XG! (CA import tariff cost you one exclamation, sorry :-))

Evan Ludeman / T8

On 29/07/2018 14:40, Tango Eight wrote:
> 18m here http://wgc2018.onglide.com/current-day.xml?class=18meter
>
> Anyone know how the live tracking speeds are calculated? I see guys flying together with speeds that don't correlate with start times.
>
> Go 70!! Go 5E!! Go XG! (CA import tariff cost you one exclamation, sorry :-))
>
> Evan Ludeman / T8
>

As far as I know it uses the same method of calulating distance as a
scoring program. Start time, rounding TPs and current location come from
monitoring the flarm position. Given distance done and time from start
gives the speed.

The onglide software is however at the mercy of the quality of flarm
coverage so if a particular glider has poor coverage near the start or
TPs then it can miss the location at some critical times. This leads to
cases where the software doesn't register that a glider has started or
rounded a TP. Clicking on the flag for a contestant will bring up the
details and you can see what it thinks is the next target.

What is normally the case for the situation you describe is that for a
glider showing a much slower speed it has

1)Missed the correct start time i.e. the last crossing of the start line
so it is using an earlier start time from a previous crossing of the
start line whilst milling around waiting to start. or

2) Missed the fix for rounding a TP so their scoring distance for the
calculation doesn't increase leading to their speed dropping off from
that point onwards.


Remember that you can click on the different icons multiple times to
show different versions of the data. Clicking through to "Actuals" from
"Handicapped" removes a few idiosyncrasies that show early on in the
flight which is an artifact of scoring UK handicapped comps even though
in this comp there is no handicapping.. Clicking on the height icon
also changes to height above ground which can be more informative as the
they start with a ground level of ~1600ft at Hosin.


--

Nick Hill