[mookey]

Thanks! It's without a doubt a pretty painful process. I'm using d3.js (https://d3js.org) for projecting a vector representation of a specific area. There is a lot of great tutorials / videos out there so a good starting point is probably just to search for e.g. "d3.js maps". D3.js might seem overwhelming at first, at least it did for me, don't let that discourage you. There are many vector sets where existing countries are already present but in my case I have to plot the highlighted map areas on my own. For that I use QGIS (https://www.qgis.org/en/site/), then just save those areas in a vector file and project them onto the map. I guess that's the basics. I have spent many, many hours generating/mapping the background image, pruning the data files from redundant information, repositioning tooltips after a zoom, etc, but perhaps you don't have to, so cross that bridge when you get there.

[randomluck040]

Sorry for answering this late and thanks a lot for the recommendation. I'll definitely take a look at d3js.org since our current solution works on top of a geoserver which has performance issues when we try to load rather large polygons and working with it is a frustrating process overall. The learning curve for the current solutions we have was steep as well so I'm not too scared (yet haha). Thank you!