Keith JenkinsMay 9

Are there established algorithms for numbering points on a map so that it is easier for the viewer to find, for example, "point 57"?

The exact order doesn't really matter, but points close together would have close numbers.

I guess this has some similarities to the travelling salesman problem, although in this case there are no line networks connecting the points. (I'm dealing with a map of about 600 trees around a group of buildings.)

#cartography #qgis

Show threadKeith Jenkins

Following up on the problem of efficiently renumbering hundreds of points on a map, the person working on this ended up asking his mathematician friend for help, and they used MATLAB to solve the Travelling Salesman Problem to generate suitable label numbers.

Also, I found that Whitebox Workflows for QGIS plugin has an implementation of the TSP which works great, and even lets you set a time limit on the optimization.

Jun 23 at 8:50pmWeb
Show threadKeith JenkinsJun 26
Although the TSP order is generally pretty good for numbering points, I'm still not completely happy with it. I'm sure it would make more sense, to someone walking around to these trees with the map, if trees 1,2,3 were grouped with 153,154,etc and trees 4,5,6,7 were inserted into the sequence with other trees in the circle.
Show threadKeith JenkinsJun 26
Ideally, there would be variant of the TSP solver where additional costs could be assigned to network lines going through buildings. (The TSP tools we used don't actually accept any network input, and simply use the point coordinates.)
Show threadKeith JenkinsJun 26
I spent about 5 minutes starting to see if I could improve it with just a few manual modifications, but quickly realized there is no obvious end to such a process, and that is not how I want to spend my time today.