Dear community, dear @mostapha and @chris,
Please ask me answer the question. In LB, the default north (which points up in the positive y-direction), is that magnetic north or true north? The default north is also known as 0 degrees.
This is important for me to know - i.e. whether or not I must correct for magnetic declination.
Thank you.
/Tom
It is true north and it will always be true north (unlike magnetic north, which changes over time and you would have to enter the date of measurement along with the north angle if you wanted it to be accurate).
@djordje had put together a component in Legacy Ladybug that could covert magnetic north to true north called the Ladybug_True North component. It looks like it only worked for the years between 2015 and 2020.
If this is something that several people need, we can prioritize adding it to the LBT Ladybug plugin.
Hello,
@chris thank you for replying on this topic.
Ladybug’s True North component, never stopped working.
It just requires free .COF file as an input. Attached is an example:
True_North-Magnetic_North.gh (375.2 KB)
The .COF file for 2020-2025 period, can be downloaded from NCEI website for free:
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Thank you @chris and @djordje
I’ll use this solutions and respond with feedback if necessary.
Kind regards
/Tom
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Dear @chris and @djordje ,
yes, I checked and true north fully coincides with positive Y-direction (it was as simple as confirming from the stereometric diagram in the Rhino scene generated by the LB_SunPath component).
The LB_True North component should be useful. But most important is for LB tool users to note whether the north given on e.g. a drawing, or site map is true north or magnetic north. If direction corrections are not made where required, errors can arise.
Thanks for the information.
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Hey @tomsanya ,
This is just to let you know that I updated @djordje 's code and I just pushed a component for the LBT plugin that does effectively what the Legacy component did:
The only difference is that I have updated the default coefficients of the WMM to be for the latest model (from 2020-2025). And updating for future releases of updated coefficients by NOAA should be pretty straightforward since it’s just a matter of replacing the COF file that’s in the ladybug Python package: