Question

How to Calculate Angle in Degrees From North

13 years ago
Apr 28, 2013 11:05 PM UTC
3 replies
381 views

matthewbrucker

I am currently using the NeighborFinder to calculate the distance and direction between two points.

However, angle (direction) is calculated from the x-axis, counter clockwise. Is there an easy way for me to calculate the angle from the y-axis (ie north) clockwise?

Otherwise, I may be stuck doing some fuzzy math to rotate and flip the numbers!

Thanks in advance for any help.

Mattt

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takashi
13 years ago
Apr 29, 2013 2:57 AM UTC

Hi Matt again :-) Try these formulas: t = 90 - s (0 <= s < 90) t = 360 - (s - 90) = 450 - s (90 <= s < 360) s: counter clockwise angle(degree) from x-axis t: clockwise angle(degree) from y-axis Which formula should be applied depends on the value of the original angle i.e. counter clockwise from x-axis.

If you are using FME 2013 SP1, an AttributeCreator with 'Conditional Value' setting would be efficient. If not, test whether the original angle is less than 90 or not, then use 2 AttributeCreators (or ExpressionEvaluators) for each formula separately.

Takashi

Why not inspect features with Visual/Data Preview and Feature/Record Information before writing them into a destination dataset?