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Author Topic: How to get a new database for the earth's magnetic field  (Read 1116 times)

Hardy Heinlin

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    • Aerowinx





Introduction

PSX update 10.130 has introduced the option to load an external database file for the earth's magnetic field. When such a file exists in the Aerowinx/Terrain subfolder during simulator start, PSX will automatically load it and use it. If the file doesn't exist, PSX will use its internal magnetic field model from 2019.

The file must have a specific format and file name. The file can be generated on a special NOAA website and can be directly downloaded to the Aerowinx/Terrain subfolder. The process takes just a few seconds.





Where can I generate the file?

Here: https://www.ngdc.noaa.gov/geomag/calculators/magcalc.shtml#igrfgrid - The website looks like this:





Note the yellow panel; this is your calculator. There you set some reference values before starting the calculator.





What values must be set?

The setting must look like this:





Every field and checkbox must exactly be set as shown above, except for the following:

• You may select the WMM model or the IGRF model. I don't know which one is better. The differences are microscopically small. I recommend the IGRF model because the file will be smaller (the WMM file will include additional data that PSX won't read anyway).

• You can set the year, month, and day as you like. But the start date and end date must be equal! In the day fields I recommend to set 15; this assures the month display in PSX will not be rounded to the previous or next month.

Recheck that all settings are correct (89, 89, 1.0, 180, 179, 1.0, 0 etc. and the checkboxes S, N, W, E etc.). Then click the blue Calculate button below the yellow panel (not on this screenshot but on the actual NOAA website).





Where should the file be downloaded to?

When the Calculate button is clicked, your browser will pop up a window asking what you want to do with this file. Select "Save File", then click "OK" (the exact wording may vary from browser to browser).

Another window will open where you can select the file destination. Select your Aerowinx/Terrain folder. You can also select a different folder, for example, your Desktop, and after the download you can manually move the downloaded file from the Desktop to your Aerowinx/Terrain folder.

The calculator will name the file igrfgridData.csv. Don't change that name. By the way, the calculator will set this "igrf..." file name even if the WMM model has been selected.

Now click OK to start the calculation-and-download in one go. If the WMM model has been selected, the file size will be circa 4.1 MB. If the IGRF model has been selected, it will be about 3.6 MB. (Note that the IGRF file includes the same amount of PSX relevant data as the WMM file.)

When the file is downloaded and if you use multiple networked PSX instances, copy the downloaded file to the Terrain subfolders of your other Aerowinx folders as well. It's important that every networked PSX instance loads the same magnetic field data.





How do I load the new file in PSX?

Just restart PSX. PSX loads the file during simulator start (when the start progress is between 79% and 80%).





Where can I check whether PSX has loaded the file?

Go to Instructor > About and find the line starting with "Earth's magnetic field":




The line "Earth's magnetic field" is followed by a database identifier. For example:

IGRF2019 FEB 2019 - Identifies that PSX is using its internal magnetic database from 2019.

IGRF2020 MAR 2021 - Identifies a loaded file based on the IGRF model of 2020, valid for March 2021.

WMM-2020 MAR 2021 - Identifies a loaded file based on the WMM model of 2020, valid for March 2021.





Can I check whether the file contains plausible data?

Go to Instructor > Situation > Position,
select the "World" section, activate the Terrain display, and select the "Mag" checkbox:




What you see now should approximately look like this (internal database from 2019):




Or like this (loaded file from 2021):




Now this is just to demonstrate that the differences are very small. These tiny differences are not related to the plausibility check. To see that the file contains a plausible dataset, just check that the displayed texture doesn't contain any straight, long edges; that would be a sign of an incorrectly formatted database file. Those tiny pixelated corners are normal.

(The global magnetic field model is quantized in 64800 small tiles. Each tile is one latitudinal and longitudinal degree in size, so there are 360 x 180 tiles. The simulator interpolates the values between the tiles internally. The map doesn't show the interpolation.)





How often should I generate a new file?

Once a year. Or once every two years.





« Last edit: Mon, 15 Feb 2021 00:11 by Hardy Heinlin »

asboyd

  • Join date: Jan 2012
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Re: How to get a new database for the earth's magnetic field
« Reply #1 on: Mon, 15 Feb 2021 01:15 »
Amazing work. File generated and loaded OK.

Thank you Hardy :)

AlexB
Alex Boyd... Sydney, Australia

Bastien

  • Join date: Feb 2014
  • Location: France
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Re: How to get a new database for the earth's magnetic field
« Reply #2 on: Mon, 15 Feb 2021 07:30 »
Hi Hardy,
Thank you for this great feature.

G-CIVA

  • Join date: Dec 2009
  • Location: Adelaide, South Australia
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Re: How to get a new database for the earth's magnetic field
« Reply #3 on: Mon, 15 Feb 2021 07:55 »
Hardy,

Many thanks for this wonderful new feature.
Steve Bell
aka The CC

Robert Staudinger

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Re: How to get a new database for the earth's magnetic field
« Reply #4 on: Mon, 15 Feb 2021 12:10 »
Servus Hardy,

Thank you.

cavaricooper

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Re: How to get a new database for the earth's magnetic field
« Reply #5 on: Mon, 15 Feb 2021 13:52 »
Hardy-

As much as it pains me to utter these words, there may well come a day when the last 744 lands permanently, after which, PSX may well be the sole way to experience 747-400 flight.  On that day, Joe Sutter will christen you "The Last of the Incredibles".

BZ

C

PS- Is there a "preferred date" for updates (Jan 1, June 1 etc.)?  BTW, my update also went smoothly, ta!
« Last edit: Mon, 15 Feb 2021 15:37 by cavaricooper »
Carl Avari-Cooper, KTPA

jtsjc1

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Re: How to get a new database for the earth's magnetic field
« Reply #6 on: Mon, 15 Feb 2021 16:16 »
Again Hardy thank you so much for your tireless work.
Joe

Hessel Oosten

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Re: How to get a new database for the earth's magnetic field
« Reply #7 on: Mon, 15 Feb 2021 18:38 »
1. Speech-less !!!

2. Fun, you know us ....:

 """Then click the blue Calculate button below the yellow panel (not on this screenshot but on the actual NOAA website)."""

3. Thanks.

H.

Hardy Heinlin

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    • Aerowinx
Re: How to get a new database for the earth's magnetic field
« Reply #8 on: Mon, 15 Feb 2021 18:54 »
PS- Is there a "preferred date" for updates (Jan 1, June 1 etc.)?

December 24

Markus Vitzethum

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Re: How to get a new database for the earth's magnetic field
« Reply #9 on: Tue, 16 Feb 2021 13:54 »
Amazing work, thanks a lot.

Just to have some fun in areas where a change of variation matters most (and where the 747-400 still sits in magnetic heading mode), here is a comparison of the magnetic heading for 1997 (PS1 release data) and 2021 (today).



(Edit: the images don't show up ... did I miss something?)

... 22 degrees of change in variation.

Markus
« Last edit: Tue, 16 Feb 2021 21:10 by Markus Vitzethum »

Hardy Heinlin

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Re: How to get a new database for the earth's magnetic field
« Reply #10 on: Tue, 16 Feb 2021 15:23 »
(Edit: the images don't show up ... did I miss something?)

I can see the images.

Will

  • Join date: May 2009
  • Location: Chicago
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Re: How to get a new database for the earth's magnetic field
« Reply #11 on: Tue, 16 Feb 2021 16:15 »
Interesting, I see the images in Safari, but they are not present in Chrome.

Magnetic field data successfully installed though, thanks for the enhancement!

I'm waiting for a creative-type to edit the CSV file to make an anomaly in the Bermuda triangle...
Will /Chicago /USA

Jeroen Hoppenbrouwers

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Re: How to get a new database for the earth's magnetic field
« Reply #12 on: Tue, 16 Feb 2021 17:23 »
I see them in Firefox.

Hardy Heinlin

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Re: How to get a new database for the earth's magnetic field
« Reply #13 on: Tue, 16 Feb 2021 17:28 »
They are not https.

DougSnow

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Re: How to get a new database for the earth's magnetic field
« Reply #14 on: Thu, 18 Feb 2021 21:59 »
Just an FYI the latest available service bulletin for the 747-400/-8 is just a 2015 MagVar table. Boeing has also published lists of airports where the current Mag variation exceeds the limit as a function of the age of the MagVar table in the ADIRU and that Autolands or NDB approaches are now prohibited.

funkyhut

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Re: How to get a new database for the earth's magnetic field
« Reply #15 on: Fri, 19 Mar 2021 06:30 »
Thank You.
Greetings from the mountains of Northern Thailand (VTCC),
Chris Stanley.

United744

  • Join date: Oct 2014
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Re: How to get a new database for the earth's magnetic field
« Reply #16 on: Sun, 21 Mar 2021 11:41 »
Just an FYI the latest available service bulletin for the 747-400/-8 is just a 2015 MagVar table. Boeing has also published lists of airports where the current Mag variation exceeds the limit as a function of the age of the MagVar table in the ADIRU and that Autolands or NDB approaches are now prohibited.
Interesting the real thing isn't updated!

I presume no operator has newer than 2015 data??

@Hardy: thank you for this feature!

DougSnow

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Re: How to get a new database for the earth's magnetic field
« Reply #17 on: Mon, 22 Mar 2021 09:55 »
I think an updated table will be available in the 2024-2025 time frame if I am not mistaken. By then the current 2015 data will be out of tolerance for those airports in very Northern latitudes, if NDB or Autolands are required.