Units conversion factors

Please use this forum to post feedback and suggestions related to QCAD.

Moderator: andrew

Post Reply
CVH
Premier Member
Posts: 3364
Joined: Wed Sep 27, 2017 4:17 pm

Units conversion factors

Post by CVH » Wed Aug 24, 2022 7:15 am

Andrew,

Looking into conversion factors for U.S. survey Feet/Inch/Yard/Mile I stumbled on:

RS.Astro = 149 600 000 000m (+14ppm)
Since sept. 2012 that is defined as exactly 149 597 870 700 meter
Internationally represented as 'au'.

RS.Lightyear = 9 460 731 798 000 000m (+0.14ppm)
Since 1984 defined as exactly 9 460 730 472 580 800 meter

RS.Parsec = 30 857 000 000 000 000m (+7ppm)
Since 2015 defined to the nearest meter as 30 856 775 814 913 673 meter

What I don't seem to pinpoint is what other CAD systems use for these conversion factors ...
Or what the dxf standard is ... And if that is updated ...
ezdxf uses the exact factor for 1au but not for Lightyear and Parsec.


Further:
In RUnit.cpp there is a trace of a unit called 'Plu' = 0.025mm what is about one 'Mil'.

Also, if I am not mistaken then isMetric() would return true for RS.Microinch.

Regards,
CVH

Post Reply

Return to “QCAD Suggestions and Feedback”