Calculation methods
The formulas, worked examples, assumptions and limits behind every tool.
Trim a track ↗
All segment points receive a global 1-based index. The chosen range intersects each segment separately.
Example: Keeping points 3–8 returns six points. A segment break inside that range remains a break.
Only track and route coordinates, optional elevation and valid timestamps are retained in normalized output. Metadata, waypoints and extensions are not copied.
Merge tracks ↗
Segments are concatenated as distinct GPX track segments. Distance is summed within each segment only.
Example: Two distant tracks remain two segments, so the gap between them does not inflate route distance.
Maximum four files, 4 MiB each, 8 MiB combined and 10,000 points combined. File order is visible and adjustable before processing.
Simplify points ↗
Iterative Ramer–Douglas–Peucker uses great-circle point-to-segment distances. Each segment is processed independently.
Example: A perfectly straight three-point segment reduces to its two endpoints at a positive tolerance.
Tolerance is 0–1,000 metres. Zero keeps all points. A bounded operation budget protects the page from pathological tracks. It is not a map-matching tool.
Clean for sharing ↗
The output is rebuilt from validated coordinates and selected fields; source metadata and extensions are omitted in every mode.
Example: With Remove timestamps selected, output contains no time elements while latitude and longitude remain unchanged.
Coordinates still reveal the route and its start/end locations. This is field removal, not location anonymization. The original files are unchanged.
Units and numerical limits
Conversions use 1 inch = 2.54 cm, 1 mile = 1.609344 km, and 1 avoirdupois ounce = 28.349523125 g. Empty, non-finite, out-of-range and unsupported values are rejected. Displayed values are rounded; calculations retain precision. Input-specific limits are reported alongside the field when exceeded.
GPX schema · Topografix ↗