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How to push an route to follow a precalculated coordinate po
Posted: Mon Sep 10, 2018 8:50 am
by branko.spiljak
Hi,
For a specific reason we calculated the polygon of our route with an external engine and now we need to calculate a similar route with xRoute because we need special xRoute output for further processing. How can we ensure that xRoute.route object is compareable to our external polygon?
Re: How to push an route to follow a precalculated coordinat
Posted: Wed Sep 12, 2018 7:52 am
by Bernd Welter
Hello Branko,
here's the response from DEV - translated and extended by myself:
Challenging... First of all it depends on the matching between the 3rd party coordinates and PTVs street network and on how dense the coordinate sequence is. Probably it is the easiest was to use an ExceptionPath object with the polyline approach though there are some restrictions. Here's what you have to consider:
- the external coordinates will be linked to PTVs segment and those will be assigned a malus value which will make those segments attractive for the cost function. But this doesn't prevent the router from choosing the wrong side of the highway (which could cause loops). So there's no proper map matching. Furthermore the ExceptionPath doesn't consider ferries.
- A better approach is to perform a map matching in a preprocessing step. The returned polyline is a better qualified input for the router in step 2.
- Another aspect of the task is the routing profile. The profiles used in the external engine should be compareable to the ones in xRoute. Whether distances and driving times match will show up afterwards, e.g. there might be a truck blocking in the PTV data which is not content of the external engines map.
Long story short: we do not have a 100% recommendation for this process (due to "we haven't done this by ourselfes so far") - you need to practise and adapt.
Best regards,
Bernd (XSERS-1124)