On Tuesday, August 20, 2013 1:55:53 PM UTC-7, Eric Greenwell wrote:
jfitch wrote, On 8/11/2013 9:59 PM:

It makes a difference if you are trying to relate your thermaling

track to a track projected to the ground. Some thermal assistants

(like SYM) draw a track on the ground color coded by climb rate. If

you are drifting with the wind, this track quickly drifts upwind

relative to you and the airmass (which are drifting downwind).



The Thermal Assistant in my version of SYM does not draw a track on the

ground (of course, the map shows the ground track); instead, it opens

it's own window with no map info on it, and uses about 20 or so small

circles ("bubbles") arranged uniformly in a large circle to display the

thermal. Each bubble is sized and colored to depict the lift at that

point: bigger bubble, bigger lift; red is stronger, blue is weaker (the

actual colors can be selected)



In essence, your circles do overlay each other, no matter how much the

glider drifts with the wind. I never had trouble with wind drift when

using the Assistant. ClearNav, what I am now using, does use a ground

track, and it's hard for me to make sense of the the thermal is doing

from it's depiction. I'm nagging them about this, and I hope it will be

improved soon.



--

Eric Greenwell - Washington State, USA (change ".netto" to ".us" to

email me)

- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm

http://tinyurl.com/yb3xywl

The latest version of SYM draws a color coded ground track, as well as the bubbles. Still has quite a ways to go to catch up with what Winpilot had in 2005....