My quick 2 cents - A lot depends on the sort of data you have to play with and where you want to do the processing ( In memory, DB or front-end ) Here's a few spots that you should explore if you haven't already:

• The Geo::* namespace is filled with gems.
• GDAL is your friend.- CLI and process with Perl or use a Module
• OSM is excellent
• Osgeo
• OSM and OSRM
• MySQL has Spatial but PostGIS remains the winner
• Front end be sure to consider Open Layers 4 has some powerful front end capabilities
• Leaflet for a little more lightweight front-end
• The GIS Stack Exchange - bit quiet lately but worth a look
• D3.js is surprisingly capable with mapping

Don't feel like you have to go with a platform - DB+A few Tools+A front end+Some Perl Glue can be a powerful combo without getting locked into a heavy opinionated application platform.