Skip to content
HackIndex.io

Triangulation and Multi-Source Verification

3 min read Created Aug 10, 2026 Last updated Aug 10, 2026

Overview

A single clue suggests a location, intersecting clues prove it. Triangulation combines multiple independent observations, sightlines from different photos, fixed geometry matched against imagery, and surrounding features from map data, so that only one point on Earth satisfies all of them at once. Verification then stress-tests that point against every source before it is reported.

Triangulating the Exact Point

When you have more than one image of a scene, or one image with several landmarks, the location is where the constraints intersect:

  • Draw a sightline from each identifiable landmark in the direction it appears in the photo. Two or more sightlines cross at the camera position.

  • Match fixed geometry, the angle between two streets, the distance from a building to a shoreline, the number of storeys, against overhead imagery until only one spot fits.

  • Use the surrounding-feature layout from map data as an independent constraint that the candidate point must satisfy.

mapchecking.com measures real-world distances and areas on a map, which lets you check that a measured distance in the image, for example the gap between two buildings, matches the candidate location.

Cross-Checking Every Source

Before asserting a location, confirm it holds across independent sources and dates:

  • Overhead footprint from satellite imagery matches the deduced geometry.

  • Ground view from street-level imagery matches the target photo's viewpoint.

  • Surrounding features in map data match what is visible in the frame.

  • Shadow-derived time and any visible weather are consistent with the claimed date.

A location that survives all four is defensible. One that fails any of them needs revisiting, not reporting.

Coordinate Formats

Different tools and reports expect different coordinate notations. Convert the final point into the formats your workflow needs:

  • Decimal degrees, for example 48.858233, 2.294500, the default for most APIs and mapping tools.

  • Degrees, minutes, seconds, the form EXIF and many official records use.

  • MGRS and UTM, common in defence and survey contexts.

  • Plus Codes (Open Location Code) and what3words, compact human-shareable references.

Convert decimal degrees to a Plus Code, or the reverse, with the Open Location Code library:

┌──(kali㉿kali)-[~]
└─$ pipx run --spec openlocationcode python3 -c "from openlocationcode import openlocationcode as olc; print(olc.encode($LAT, $LON))" 
8FW4V75V+8Q

Documenting the Chain of Evidence

A verified location is only useful if the reasoning is reproducible. Record, for each conclusion, the source image, the clues extracted, the reference or imagery used to confirm each clue with its date, and the final coordinate in the required formats. Save dated screenshots of the confirming imagery, since archives change and a link alone may not reproduce what you saw. This chain is what lets another analyst independently arrive at the same point.

References