I'm trying to migrate my desktop GIS application from Bentley Map to QGIS. Everything seams to be transitioning great, expect the rotated points. The rotation angle they were saved in Bentley was in radians. I have tried using the mathematical formula (degrees = radians * 180 / pi) to convert them, but It doesn't get me the right angle.

Is there another way to do It?

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    Can you give an example value, what result you are getting and what you're expecting? – Mintx Apr 13 '15 at 22:00
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    Perhaps the default orientation isn't what was stored. ArcGis has two options: Geographic (default) North = 0, increasing clockwise; Arithmetic (cartesian) East = 0, increasing counter clockwise. Perhaps your angles are Arithmetic - try that and see if it looks better. Note that symbols have a rotation too, to rotate correctly the symbol should be pointing 'up' in the TOC. – Michael Stimson Apr 13 '15 at 22:06

Well, I just came with the answer!

Searching for PyQGIS codes I found this guy who came with the formula below:

360 - (radians / pi) * 180

It worked perfectly!

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    That formula converts arithmetic to 90 offset geographic to accommodate 'right pointing' symbols. It will produce a result with the symbols correctly oriented on a map product but is not strictly speaking 'correct'. – Michael Stimson Apr 14 '15 at 0:53
  • Thank you, Michael. I'm not sure I fully get your explanation (My fault, I knew those math classes were important...). I checked the values, as you said, they show the right inclination and the angle never go beyond 360. Is there a problem to convert them to degree like that? – A. Jesus Apr 14 '15 at 11:32
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    There's no problem so long as you're the only one using the data, the next user may experience difficulty without an explanation of the angles. By convention, symbols to be rotated are at 90 degrees to non-rotated symbols (don't ask me why, I wasn't the one who did it) so pointing 'up' in the symbol selector is 0, by having a 90 offset you can use 'pointing right' (default) instead. If I knew how important math and algebra were going to be to me now I would have paid much more attention in high school - fortunately Google gives me most of the answers, if I can understand them. – Michael Stimson Apr 14 '15 at 21:11

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