It is possible to do it out of the box.
The app comes with a '/app/heremaps/linemap2' and '/app/heremaps/linemap3' dashboard, have a look at them.
They are not shown in the menu, but you can open them by modifying the url.
Or just open the 'linemap1' dashboard and use the following search:
|inputlookup line-data2.csv |head 13 | tail 1 | eval coords=split(coords,";") | eval points=split(points,";") | eval values=split(values,";")
Customizing the visualization is possible by setting the different options of the line map.
Hope this helps,
Are you asking about this app https://apps.splunk.com/app/1628/ ?
It can draw route with a line, more than that it actually draws routes.
But if you want something more from it - you can easily change it for your needs https://github.com/splunk/splunk-demo-app-routemap