Nik4 VS derive

If you have postgresql + postgis and mapnik at hand, you could try using Nik4: it takes a bounding box or a target size with a scale and produces a rendered image. But you would need to load the data yourself. And in the style you can just disable layers your don't need, like labels. And yes, this tool can export an svg.

It's not trivial, but another option if you have access to a rendering setup, there's a script with lots of options: https://github.com/Zverik/Nik4

From there, you will need to take your exported GPS track files, and combine them, so they show up on a single map. I use https://erik.github.io/derive/, which loads the file within your own browser and doesn't send the tracks to anyone's servers.

I then use https://erik.github.io/derive/ to load all those GPS tracks, and it overlays them as a heatmap. Gives you a really nice overview of where you've been over time.

derive is pretty cool online heatmap tool. I'm sure there are plenty of other alternatives out there. :)

I've tracked the majority of my rides using strava on my phone, then downloaded the data and uploaded to a guy's app called Derive. It doesn't allow you to download an image so I captured a collage with snipping tool and composited them together with ICE.

Or dérive?

If you have the GPS track files for your runs, I've had pretty good luck using https://erik.github.io/derive/