Convert CSV (spreadsheet) to KML

Sometimes the only question is what a route looks like on the ground, and KML — the format Google Earth reads natively — answers that faster than any fitness app can. This tool takes a CSV built to FitFileHub's documented schema (timestamp, lat, lon, elevation_m, and whatever sensor columns are present, with common alias headers tolerated too) and writes just the geometry: a placemark path with coordinates in KML's required lon,lat,ele order, reversed from the CSV's own lat/lon column layout. That reordering is handled automatically, along with folding elevation into the same coordinate tuple KML expects rather than a separate field. Heart rate, cadence, power, and any lap-index values in the source CSV have no equivalent in KML — it's a pure geometry format with no schema for sensor data or workout structure — so those columns are left out of the output entirely rather than approximated. What matters for this conversion is the precision of the path itself, and position, elevation, and timestamps, where present, all carry over exactly. The result opens directly in Google Earth, My Maps, or any KML-reading mapping tool for a clean visual of the route. As with every FitFileHub tool, the conversion runs entirely client-side — no upload, no account — with a background worker handling large files without freezing the page.