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Fair weather scenario - Basic Weather vs. Advanced Weather

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Fair weather scenario - Basic Weather vs. Advanced Weather

Postby dg-505 » Thu May 12, 2016 9:47 pm

Hi :)

I noticed something:
When setting the weather scenario to fair weather, the QNH (property: environment/pressure-sea-level-inhg) differs depending on the weather engine. The METAR string says QNH is 1015 which is about 29.972 inHg. With Basic Weather the property environment/pressure-sea-level-inhg is set to exactly that value.

However in Detailed Weather, the property is set to 30.47 which would be a QNH of 1031 hPa.

Is it intended that the difference is that high or is it a bug? Which factors affect the property environment/pressure-sea-level-inhg?

Thanks
Jonathan

Edit: The ATIS-Lady tells a QNH of
One-Zero-One-Three hectopascal or Two-Niner-decimal-Niner-Two inches

which suits for none of these scenarios...
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Re: Fair weather scenario - Basic Weather vs. Advanced Weath

Postby sanhozay » Thu May 12, 2016 10:16 pm

As discussed recently on the mailing list, environment/pressure-sea-level-inhg is not the QNH. I made a fix a couple of weeks ago that ensures ATIS offers the correct QNH when using real weather (metar/pressure-inhg) but I didn't extend what I was doing into weather scenarios.

When did you last pull and rebuild 2016.2.0 (or fetch a nightly build)?

I was planning to look into this a bit more after the 2016.2.1 release?
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Re: Fair weather scenario - Basic Weather vs. Advanced Weath

Postby dg-505 » Thu May 12, 2016 10:46 pm

Ah, okay, I see.

My nightly build is a few days old.
I noticed that the QNH announcement in real weather is correct, thanks for your work.

Looking forward to further developments ;)
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Re: Fair weather scenario - Basic Weather vs. Advanced Weath

Postby Thorsten » Fri May 13, 2016 4:29 am

'Fair weather' doesn't select a METAR but the offline weather engine with an AW core high pressure tile - which starts with a randomized pressure value. It's a device of the dialog to (intentionally) hide that from the user - the displayed METAR string is largely fake in these cases.

If you think this is a bad idea, please discuss it wit Stuart, I didn't make that dialog, though I can live with it - and I acknowledge it tries to put a lot of different concepts and philosophies under one surface.

If you actually want to run AW using a METAR string and have the exact weather as given in the string, you need to run it in METAR mode, then it will default to the given pressure. It won't change then of course until a new METAR comes in.
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