line graph weird shape, multiple y's for x

This is an artifact of the point connection method used to draw the line.

You should use the Chart Series Formatter to change from "Curved":

To "Straight":

Hi jojost,

It looks like you are adding a Connection Line

Numbers will try to fit a line, but that line will be just a "best guess".

Perhaps a moving average will show what you want:

Regards,

Ian

i wouldnt say its a bug, you asked for curves between the points, which means...

it must develop a curve from point 0 to 1,

then a curve from point 1 to 2. now...

it must connect those two curves -with a curve-,

This could result in an off looking curve connecting two points, like you see. Where the curve from 0-1 must be decreased to come back to the curve calcuated for 1-2.

Jo

Does it look weird? Yes?

Is it a bug? I would say "No"

Noone in these forums works for Apple so I am guessing that they are using a similar method to draw the connection as a curve that they use for the "Draw with Pen" method of drawing a line:

I drew a line using the "Draw with Pen" method on top of the points in your data (the purple line, one click for each point of your data):

select the line, then double click the line. Each point will become a red outline with white center. The point you click change to have a red center. If you double click the point you will see little round controls with a point in the middle connected to the point with a line. You can draw those to control the slop of the curve at that point. The length of the line from the control to the point defines the weight of the slope. As you can see I can get a similar shape.

You should be careful about using a shape like this to interpolate data from discrete data. Ian suggested an average that will not show this phenomenon but will add a delay (or time shift) to the curve,

Hi jojost,

I am playing the Devil's Advocate.

To get a curved line of "best fit" you would have to use a polynomial equation with many, many powers of x.

That equation would not make sense to humans.

Perhaps we should cut to the main aim. What are you trying to illustrate in that graph?

Regards,

Ian.

Here is a plot using a trendily (as Ian suggests) showing a order 6 polynomial:

I agree we should understand WHAT you are trying to show with the curved data.

Also... is the data you are posting as an example real data or made up?

I do not think the the curved connection method is appropriate for high dy/dx (or dy/dt) kind of data.

Please select the original data from the table, then copy and paste here (if the data is not sensitive).

Can you also address what are you trying to show (specifically with the curved, instead of straight, connection)?

Straight is you best option

Agreed.