3 Replies Latest reply on Nov 1, 2018 7:31 AM by KOCHIN CHEN

    On Great Circles

    William Hall

      During the last presentation there was a query on displaying great circles in Tableau.

      There are two articles on the matter. Both depend on generating KML files which can be imported into Tableau from which Tableau will generate the paths. The exact mechanics depend on the version.


      The article at Flights of the World Part II: How to map great circle routes in the newest Tableau release | Tableau Software describes how from version 2018.2 it is possible to import a KML file with just co-ordinates for origin and destination and this will be recognized as spatial data and plotted with great circles instead of straight lines. I've attached an example KML file with NDOD based on the data sources refereed to in the article. By importing this into 2018.2 it is quite straight forward to construct an appropriate map.


      The article at Flights of the World: How to map great circle routes in Tableau 10.4 | Tableau Public I have not tested. This professes to work for 10.4 or later and instead of an origin and destination appears to suggest generating an approximation of the arc by using a python script to add intermediate points to the path so that Tableau plots the line along the path rather than just from origin to destination.


      Either solution allows then to create a relationship with other data sources based on NDOD, O&D or however else you'd like to label up the KML file.


      Happy to invite additional discussion around the topic and other solutions that might exist or that have been implemented.