How to make a heatmap from your GPX files

The short answer

Gather every GPX file you want included into one folder — a season's worth of hikes, a year's, whatever range makes the picture worth looking at — and open them together in mapping or GIS software built to plot more than one track at once, rather than uploading them one at a time to something that only ever shows a single route. The overlap between files is what creates the heatmap effect: places where several tracks cross the same ground get drawn brighter or in a different colour than places only one track ever touched. Nothing about an individual file needs to be prepared specially for this — an ordinary recorded track, the kind almost any hiking, walking or cycling app already exports, is exactly what the process expects.

Where the "heat" actually comes from

A heatmap is not a feature hidden inside a single GPX file waiting to be switched on — it is something built entirely by the software reading many files at once and counting how often each patch of ground appears across all of them. One file, opened alone, produces one line, the same as it always would. The visual effect that makes a heatmap distinct — well-worn paths glowing while a rarely used side trail stays faint — only shows up once there is a pile of tracks to compare against each other, which is why the number of files matters more than anything about any single recording.

What a file needs to have, and what it doesn't

A heatmap only cares about where a track went, not how fast, how steep, or when. Position is the one thing every point needs, in order, and that is already the core of any GPX track regardless of which app produced it. Elevation and timestamps ride along in most exported files but do nothing for a heatmap specifically — a track with no elevation data at all overlays exactly as well as one that has it, since the software is only ever comparing latitude and longitude between files, not anything else a point happens to carry.

The wrinkle: a heatmap makes the endpoints problem bigger, not smaller

A single shared GPX file gives away where one walk started and ended. A heatmap built from months of files gives away the same thing with the volume turned up — a driveway that only shows up once in a single track becomes the single brightest point on the whole map once it appears in every file behind it, because that is exactly the kind of repetition a heatmap exists to highlight. The middle of the map, the trails themselves, is the part that was always meant to stand out; the habit of trimming a track or starting a recording once already at the trailhead matters more here, not less, once a lot of files are stacked on top of each other rather than shared one at a time.

• Leave out files that start or end at home, rather than trimming each one individually, if the heatmap is ever going to leave your own hands.
• Keep an untouched copy of your full history for yourself — a heatmap built for sharing does not need to be made from the same set of files you keep privately.

Where TrailCam fits in

TrailCam exports a single route as GPX 1.1, or your whole recorded history at once, so building a heatmap starts with an export that already exists rather than a new one made for the occasion — every hike is already a standalone GPX file the moment you export it. GPX export is part of the optional TrailCam Pro upgrade; TrailCam itself is free to download.