Isochrones with the option "avoid polygone" are larger than without

openrouteservice isochrones
1

Hello,

I have a question how the ORS algorithm is working. I created isochrones from a point layer and in the second step I did it again with the same parameters but now with the option “avoid polygones”.

For most points it worked well, but some isochrones were larger (area and population) after the second run than after the first run.

From my point of view this cannot be.

Is there an answer for this problem? Or did I make a mistake?

2

Hi,

thanks for reaching out. Could you maybe provide a concrete example illustrating the issue?

Cheers,
Andrzej

3

Hello,
here are some pictures of the issue.
And here is also a link to the dataset of two points and the avoid polygones.

Avoid Polygones
Avoid Polygones1313×730 4.03 KB

With Avoid Polygones
With Avoid Polygones1301×739 6.67 KB

Without Avoid Polygones
Without Avoid Polygones1300×734 6.24 KB

4

Thanks a lot! Would you mind providing the parameters of the isochrones you are trying to compute as well, such as profile, range, etc? Cheers!

5

Parameters:
Travel mode: driving-car
Dimension: time
Range: 30
Location Type: destination

1 Like
6

Do you have a solution for this problem now?
Thanks a lot.

8

Hi @JonasW,

thanks for your patience. I was able to reproduce the described behavior, very puzzling indeed! Unfortunately, I neither have an explanation nor a solution currently. The exact cause needs to be investigated. I’ll keep you posted.

Cheers,
Andrzej

9

All right.
Thank you for your answer.