ActivityDoctor Treats FIT Files Like Evidence

Field notes

The workflow keeps the same local FIT file across viewing, diagnosis, repair, recovery, conversion, and editing rather than splitting those tasks among separate utilities. Its diagnostics reference checksums, CRCs, messages, timestamps, anomalies, and recoverability, while the display can downsample very large activities without applying that reduction to repair logic. The route preview uses vector drawing instead of requesting third-party map tiles, and the page says analysis runs in a browser Web Worker.