# Finding the “perfect” track without using a road twice using QGIS

As a part of our work we have to scrutinize the network of roads in our forest for their timeliness. We were given the data (roads as lines and nodes) in the form of vector files. The problem with these files is that they are possibly outdated and due to that we have to countercheck them.

My idea was to create a track with some kind of analysis to lead us through each tile without having to drive some of the roads multiple times. Is there a a tool or some kind of extension to help me calculate the most efficient path?

So far I have only seen approaches to find the shortest track between two or multiple points, but this would not work for me since my prime intention is not the shortest path.

To make my problem clearer since I can not comment on my former posted question due to my lack of reputation (my registered account is fjaellraeven, Pascal was just a guest account):

At the moment I am using QGIS 2.14 Essen.

The factor I measure efficiency with is time. The situation is as follows:

The roads in the local forest are not up-to-date anymore and that is why we have to stocktake them. For this purpose I want to generate a track which is time efficient. From my point of view the most efficient path would be the one where I have to drive each road only once. The "Travelling Salesman" deals with this problem quite well.

We do not have to file the tracks we are driving so it is not about accuracy in the first place. If we encounter a missing/deviating road or one which is not accessible anymore we will digitize it later. The main intention is to check the existing roads for their timeliness.

I hope my "problem" is a little bit clearer by now. Keep in mind that the forest we have to drive along in has an extension of multiple thousand square kilometres making it kind of a huge deal if we drive inefficient and without a plan.

• The equivalent process in ArcGIS may be Route Analysis, with the centroid of each polyline as a "stop", and the option of "Reorder Stops To Find Optimal Route" checked. – smiller Nov 14 '18 at 14:23
• Apparently this is called a "Travelling Salesman Problem." Searching for "QGIS travelling salesman" brings up a number of possible solutions. Unfortunately the `TSP - optimal route` plugin uses Google or OSM roads, not your network. Try the processing toolbox algorithm `v.net.salesman`. – csk Nov 14 '18 at 17:08
• You want to calculate the most efficient path, but what means efficient. Usually you need some kind of costs (like maximum speed). If you do not have anything else, the shortest path is the most efficient path. Which Version of QGIS do you use? – AndreasK Nov 15 '18 at 10:42