Routes failing for short distances

[hscottmatthews]

First off, thanks for searoutes on GitHub! It has been amazingly helpful to us in modeling tanker routes for a public project making a distribution of distances between global energy facilities.

However, we noticed a few routes failing (returning 0.0 distances) when they were nearby. For example, the following routes:

from (lat, long) -> to (lat, long)
-6.1195700, 12.3359600 -> -4.893, 11.881
10.18106, 61.69189 -> 10.599336, -62.315522 (yes really close!)
2.935 9.91 -> 4.41836, 7.16157

Yet other routes (eg Huizhou to Shenzhen) work and show up with small distances (~10 nm)

We are easily able to just ignore these 0's, it's not a problem. Is this just an issue of "too close to route"?

Just wanted to highlight this.

[genthalili]

@hscottmatthews, thanks !

Regarding your cases, indeed the distances are very small and the resolution of the network would not be able to capture them, especially in areas whee the edges (connections) are not dense. As you have notices, around frequently used ports or terminals the network is more dense, therefore you will be able to capture even short distances.
Hope this helps.