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Old July 16th 20, 07:19 AM posted to rec.aviation.soaring
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Default How accurate are the OLC AGL traces?

On Thursday, July 16, 2020 at 6:28:25 AM UTC+2, kinsell wrote:
On 7/15/20 7:34 PM, MNLou wrote:
Hi Nick -

When I want to analyze a flight from OLC, I download the IGC file and open it in See You.

I think the AGL numbers are See You are more accurate than from the OLC summary.

YMMV -

Lou


The barometric sensor in the logger is going to be assuming 29.92 inches
of mercury for atmospheric pressure, any deviation from that is going to
introduce an error on top of the instrument accuracy. So the AGL
calculations can be off quite a bit no matter what database is used for
ground elevation..


I would suspect OLC is using GPS altitude for AGL calculations, and probably using a fairly course terrain database which would explain the inaccuracies.