Skip to main content
  • EN

Not a question, but a Tip.

 

Sometimes there is a need to convert angles measured in Arithmetic convention (counter-clockwise from the X-Axis) to Geographic convention (clockwise from North/Y-Axis).

 

capture 

For example, Transformers like TopologyBuilder output Edge angles in Arithmetic degree angles whereas Desktop GIS systems like ArcGIS can sometimes default to Geographic degree angles.

 

Instead of using complicated Conditional Value formulae to translate angles quadrant by quadrant with different formulae, searching the internet came up with a genius single formulae that converts angles back and forth, no matter what quadrant the calculated angle is in.

Geographic Angle = (450 - Arithmetic Angle) mod 360

 

Rewriting the formula into FME Maths function format it becomes this

Geographic Angle = @fmod((450 - @Value(Arithmetic Angle)),360)

It also works in reverse:

Arithmetic Angle = @fmod((450 - @Value(Geographic Angle)),360)

Great piece. This should be a transformer.

Great tip, thanks for sharing. I agree that it would make for a great contribution to the FME Hub.

Thanks for the tip!

Reply


Community Stats

30,163
Posts
114,500
Replies
37,813
Members
Terms & ConditionsCookie settings
A product of
Safe Software respectfully acknowledges that we live, learn and work on the traditional and unceded territories of the Kwantlen, Katzie, and Semiahmoo First Nations.