No check for equal proportions in plot about ggquiver

[mitchelloharawild]

Perhaps I'm missing something here, but is there a general requirement for the coordinates to be fixed? The arrows point to the same location in both plots, but have different angles when the plot's aspect ratio changes. I think this behaviour is expected when working with u and v as force offsets from the starting position.

It is definitely worth mentioning that when the arrow's angles are important, that using equal coordinate ratios for x and y axis is needed.

[mitchelloharawild]

Thanks for the reprex and clear explanation by the way! 🎉

[bart1]

No problem, maybe it is not the case for all applications, for most applications I could see for the arrows the direction does matter. I encountered this when a student had some code where the arrows were pointing in a "wrong" direction. In our case it was a time series of vectors. As I know the u and v notation mostly from wind fields there the direction is important. I would say you know better how it is used and may see what the most common applications are.

[mitchelloharawild]

For wind fields, I imagine it will be plotted on a map which would use the appropriate map coordinates. Perhaps I could add a message when the default ggplot2 coordinate space is used with geom_quiver(), suggesting that the angles may not be what is expected unless coord_equal() is used.

[bart1]

In this case we were interested in a timeseries of wind to that is why the map did not have dimensions. I think that warning/message sounds sensible.