[postgis-users] Calculate accumulative bearing given a zig-zagging line

Sandro Santilli strk at kbt.io
Thu Feb 17 03:33:49 PST 2022

On Thu, Feb 17, 2022 at 08:21:24AM +0000, Shaozhong SHI wrote:
> Is there a function for calculating accumulative bearing given a
> zig-zagging line?
> If we set a segment to travel towards north and its bearing is 0. Next
> segment may zig-zag towards 10 degrees.  The following one may zig-zag
> towards -5 degree.
> Calculating accumulative bearing may assist us to check whether a line does
> a U-turn.  If accumulative bearing is greater than 180, it is a U-turn.
> Is there such function available?

You can use ST_Azimuth, some normalization routine to turn the radians
into a signed value and the sum aggregate to "accumulate" it.


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