OLC Graph Question

[V1[_2_]]

When looking at the “Flight Details” page for specific flight, there’s
a graph in the bottom left that shows the altitude trace. Many of the
graphs just have a blue line (showing altitude) with a green shaded
area at the bottom (showing ground level).

But others (I’ve seen this for multiple different pilots) have an
added yellow shaded area at the bottom. In the few I’ve looked at,
it’s under 500m, but higher than the green (which is close to sea
level in our area). An example is:
http://www.onlinecontest.org/olc-2.0/gliding/flightinfo.html?dsId=2054654
I asked the pilot of the above graph - she didn’t know what the yellow
was.

Can anyone shed light on what the yellow shading means? Or point me
to where on the OLC there’s a good description of the Flight Details
page?

Thanks,
- Frank

[Greg Arnold[_2_]]

On 8/10/2011 7:51 PM, V1 wrote:
> When looking at the “Flight Details” page for specific flight, there’s
> a graph in the bottom left that shows the altitude trace. Many of the
> graphs just have a blue line (showing altitude) with a green shaded
> area at the bottom (showing ground level).
>
> But others (I’ve seen this for multiple different pilots) have an
> added yellow shaded area at the bottom. In the few I’ve looked at,
> it’s under 500m, but higher than the green (which is close to sea
> level in our area). An example is:
> http://www.onlinecontest.org/olc-2.0/gliding/flightinfo.html?dsId=2054654
> I asked the pilot of the above graph - she didn’t know what the yellow
> was.
>
> Can anyone shed light on what the yellow shading means? Or point me
> to where on the OLC there’s a good description of the Flight Details
> page?
>
> Thanks,
> - Frank


That is the noise level. Look at a motorglider trace such as this one:
http://tinyurl.com/3h57shw
The yellow trace is high when the engine is running, then is much lower
after that.