GPX → photo location metadata
The trail knows where.
Your camera only knows when.
Load one GPX trip and one photo folder. Make the camera clock explicit, inspect every bracketing gap, then export reversible location metadata without touching the originals.
Native macOS 14+Local processingNo account
OFFLINE TRACK PLANE
TIMEZONEAmerica/DenverCAMERA CORRECTION+60 secINTERPOLATIONBRACKETS ONLY
AR-001-trailhead.jpgExact timestamped GPX pointREADY
AR-002-ridge.jpg210s before · 390s afterREVIEW
AR-003-before-trip.jpgOutside captured track intervalNO MATCH
Inside the actual app
The clock model
stays on the table.
The Release workspace keeps source evidence, explicit timezone and correction, the offline track plane, per-photo confidence and reversible output controls in one inspectable view.
One bounded trip
From camera clock
to reviewed coordinates.
TrackExif is not a general EXIF editor or route repair tool. It does one local correlation job and keeps the evidence for every outcome.
Load a GPX and photo folder
Parse timestamped track points, inventory supported images, read observable EXIF clock evidence and capture SHA-256 source hashes.
Model the camera clock
Choose an explicit IANA timezone and preview a correction from −12 to +12 hours. Embedded EXIF offsets stay visible and are respected.
Inspect every match
Exact points and tight brackets can be high confidence. Wider valid brackets require review. Outside-track and long-gap timestamps stay unmatched.
Export new evidence
Write XMP sidecars or compatible metadata copies into a new folder with a JSON manifest, readable receipt and artifact hashes.
The confidence model
A coordinate needs
temporal evidence.
Green is not a feeling. TrackExif derives each state from where the adjusted capture instant lands against timestamped GPX points.
Exact point or tight bracket
An exact GPX timestamp, or two points no more than 120 seconds apart with each side at most 60 seconds away.
Valid bracket, wider gap
The capture still sits between two points no more than 30 minutes apart, but a person must inspect and approve that photo.
No trustworthy bracket
Missing clock evidence, a time outside the track interval, or a GPX gap over 30 minutes produces no coordinate.
Originals stay put
Two output paths.
One honest receipt.
Every eligible source is re-read and re-hashed before output. A changed photo becomes a recorded failure, never a silent success.
XMP sidecars
Write small portable metadata companions for JPEG, HEIC, TIFF, PNG and other inventoried formats without rewriting image bytes.
Sidecars/DCIM/AR-001.jpg.xmpCompatible metadata copies
Create separate JPEG, HEIC or TIFF-family copies, insert GPS metadata and re-read the coordinate. Unsupported round-trips fail visibly.
Copies/DCIM/AR-001.jpgManifest + receipt + hashes
- Per-photo confidence and decision
- Source and artifact SHA-256
- Timezone and camera correction
- Written, skipped and failed outcomes
Practical field notes
Understand the clock
before changing metadata.
Questions, with boundaries
TrackExif FAQ
Does TrackExif modify my original photos?+
No. The current workflow reads and hashes selected sources, then writes a new export folder. Choose reversible XMP sidecars, or new metadata copies for compatible JPEG, HEIC and TIFF-family files.
How are coordinates calculated?+
A photo must land exactly on a timestamped GPX point or between two valid bracketing points. TrackExif does not invent a coordinate before the first point, after the last point, or across a gap longer than 30 minutes.
What happens when the camera clock was wrong?+
You choose an IANA timezone and a bounded camera correction from minus 12 to plus 12 hours. The preview is recalculated before export, so the model stays visible instead of becoming a hidden assumption.
Do low-confidence matches get written automatically?+
No. Only high-confidence matches are immediately eligible. Every review-required photo needs its own approval; unmatched photos cannot be approved into existence.
Which files support embedded GPS copies?+
The current copy mode supports compatible JPEG, HEIC and TIFF-family images that ImageIO can round-trip and verify. PNG and any format that fails that check remain honest failures; use XMP sidecars for those files.
What does an export include?+
The export contains sidecars or compatible copies, a per-photo JSON manifest, a readable Markdown receipt and SHA-256 hashes for every payload artifact plus the manifest and receipt.
Does the app upload photos or GPX tracks?+
No. Matching and export run locally. The native MVP has no account, analytics or cloud upload path.
Is TrackExif available today?+
Not yet. The reviewer release is Developer ID signed, Apple notarized and available privately in Polar, but broad real-camera corpus testing and Polar Account Review remain launch gates.
How much will TrackExif cost?+
The planned launch price is US$29 as a one-time purchase for one Mac. Checkout stays disabled until the release gates are complete.
TrackExif for macOS
Put every photo
back on the trail.
A focused local matching desk for photographers who have a GPX trip and a camera clock—not a subscription EXIF suite.
- macOS 14+
- One Mac
- Planned one-time license
Planned launch price$29One-time purchase
The private reviewer build is Developer ID signed and Apple notarized. Broad camera/GPX corpus testing and Polar Account Review are still pending.