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Old 04-19-2019, 12:06 PM   #1
Elphaba
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Default Clever Maths people - I need your help!

This site:

http://46.101.125.20:8080

If you click on WIZARD it describes a Function / Equation that you need to enter to create a nomogram.

I'm trying to put together a PDF of a High resolution manoeuvring board in metric, and I need a nomograph for Minutes (0-200) to Metres / Kilometres (0 - 200?) then to Knots.

I'm fine with circles and triangles but equations like this and trying to create one that fits the requirement, I have no idea how to do that.

Can anyone please help?

Thanks
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Old 04-19-2019, 03:49 PM   #2
Pisces
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Seems like template #2 is the most similar to your Speed=Distance/Time. Where the third variable would need to be defined as function 1/z. But I let it generate with default settings (just to see it works) for 7 minutes now and nothing comes out. So I suspect it (or the back end) is buggy.

That's sad, as you found a nice gem in the interwebs with this one.

Last edited by Pisces; 04-19-2019 at 04:00 PM.
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Old 04-19-2019, 04:05 PM   #3
Pisces
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Yeah, 20 minutes later still nothing. Loosing the little bit of faith I had left in it just being slow. And I'm usually patient enough. Did you get any result?

There is a Windows installation procedure to let it run on your PC:
http://pynomo.org/wiki/index.php/Installation

I don't have the time to try it now. Maybe one day later I will try it. Supposedly you should be able to copy the script from the website to a text file and save it with .py extension.
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Old 04-20-2019, 01:19 AM   #4
Nathaniel B.
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Caveat: I'm no math wiz.


One Yard is 0.9144 meters - so you can pretty much use the yard scale on the existing MB as an estimation of meters (or kilometers) traveled in a given time period.


But, I did manage to modify the nomogram to make it slightly more accurate when using meters/kilometers.


Try it out and let me know what you think:


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Old 04-20-2019, 03:40 AM   #5
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Looks great. I guess you just streched the range scale to 1.09361 times the length of the original scale?
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Old 04-20-2019, 04:16 AM   #6
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Thank you.



Actually, I tried scaling it based on the proportions - but that didn't seem to work so well. What I ended up doing was compressing*/repositioning it until various pre-calculated results [mostly] matched up.


I must admit, though, that I'm not entirely sure that I got it just right. That's why I'd be very interested in anyone's test results.


*Counter intuitively, the distance scale needs to be compressed rather than stretched.
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Old 04-20-2019, 05:28 AM   #7
Elphaba
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Quote:
Originally Posted by Nathaniel B. View Post
Caveat: I'm no math wiz.


One Yard is 0.9144 meters - so you can pretty much use the yard scale on the existing MB as an estimation of meters (or kilometers) traveled in a given time period.


But, I did manage to modify the nomogram to make it slightly more accurate when using meters/kilometers.


Try it out and let me know what you think:


YOU'RE AMAZING!


Thank you SO much! That's fantastic!
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Old 04-20-2019, 05:59 AM   #8
Pisces
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Nathaniel B: The scale compression (or expansion) should not have been needed. An order of 10 on each scale should have the same difference in pixel coordinates. Only a horizontal shift of the distance scale would be needed to turn the yards into meters.

By how much? Draw a vertical line between the same mark on the time and speed scale. This crosses at a specific distance. Calculate what this should become: i.e. 10 kts in 10 minutes = 3086.67 meters. (=10min *10kts * 1852m/60 min)

Measure the pixel distance (on the original scan) between 3000m and 30000m.

Then the offset of the 3000m mark w.r.t. the 10kts and 10 minutes marks = ( log_10(3086.666)-log_10(3000) )*pixeldistance. The 3000m mark would come left of the vertical line so shift in the appropriate direction.

Last edited by Pisces; 04-20-2019 at 06:14 AM.
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Old 04-20-2019, 06:13 AM   #9
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Interesting, thanks! I'm glad to receive any input that might make it more accurate. I'll mess around with it more when I have time to test more examples.
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Old 04-20-2019, 06:16 AM   #10
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I corrected my formula above, I placed the difference of logarithms between brackets.
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