<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Mateusz,</div><div class=""><br class=""></div><div class=""> The difference is in the small component snapping.</div><div class=""><br class=""></div><div class=""> "Impossible route between points" indicates that the two snapping points are on different small-sized Strongly Connected Components (SCC) (i.e. on two separate islands)</div><div class=""> "No route between points" indicates that the two snap points are on the same component, but there is no route between them.</div><div class=""><br class=""></div><div class=""> OSRM identifies every road edge as either belonging to a particular "small component" (an SCC with fewer than 1000 nodes, e.g. an island), or "the large component" (there is only one of these globally).</div><div class=""><br class=""></div><div class=""> During initial route finding, we snap coordinates to the nearest edge.</div><div class=""><br class=""></div><div class=""> If both the start and end snap to the same SCC, we attempt to route. If the route fails, you'll get "No route between points". This can happen if you route between two locations on the global "large component", i.e. between Europe and the USA.</div><div class=""><br class=""></div><div class=""> If both coordinates snap to the same small component, then by definition, you will get a route (this is what an SCC is).</div><div class=""><br class=""></div><div class=""> If one coordinate snaps to a small component, and one to the large component, the first point will be searched to find the nearest point on the large component. Then we attempt to route.</div><div class=""><br class=""></div><div class=""> The only time "impossible route between points" can really happen is during test cases or if you fiddle with settings. Because the threshold for "small component" is 1000 nodes, there is no "large component" created during test cases.</div><div class=""><br class=""></div><div class=""> This leads us to the situation where you can snap points to two separate small components, and leads to the error "Impossible route between points". That's what's happening in your test example - the one-way roads are creating separate SCC islands.</div><div class=""><br class=""></div><div class=""> There's a blog post here that gives an overview for the reasoning behind this somewhat complicated logic:</div><div class=""><br class=""></div><div class=""> <a href="https://www.mapbox.com/blog/smart-neighbor/" class="">https://www.mapbox.com/blog/smart-neighbor/</a></div><div class=""><br class=""></div><div class="">daniel</div><br class=""><div><blockquote type="cite" class=""><div class="">On Feb 20, 2017, at 9:42 AM, Mateusz Loskot <<a href="mailto:mateusz@loskot.net" class="">mateusz@loskot.net</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">On 20 February 2017 at 13:51, Mateusz Loskot <<a href="mailto:mateusz@loskot.net" class="">mateusz@loskot.net</a>> wrote:<br class=""><blockquote type="cite" class="">[...]<br class="">I run the OSRM processing and service:<br class=""><br class="">osrm-extract.exe -p C:\apps\osrm-5.5.0\profiles\car.lua<br class="">89_car_two_consecutive_oneways.osm<br class="">osrm-contract.exe 89_car_two_consecutive_oneways.osrm<br class="">osrm-routed.exe 89_car_two_consecutive_oneways.osrm<br class=""></blockquote><br class=""><br class="">FYI, I've tested those queries using build based on the latest master<br class="">and I'm getting the same results as on Windows with OSRM 5.5.0.<br class=""><br class="">Best regards,<br class="">-- <br class="">Mateusz Loskot, <a href="http://mateusz.loskot.net" class="">http://mateusz.loskot.net</a><br class=""><br class="">_______________________________________________<br class="">OSRM-talk mailing list<br class=""><a href="mailto:OSRM-talk@openstreetmap.org" class="">OSRM-talk@openstreetmap.org</a><br class="">https://lists.openstreetmap.org/listinfo/osrm-talk<br class=""></div></div></blockquote></div><br class=""></body></html>