Chronolocation & Suncalc Shadow Analysis: Pinpointing the Exact Time and Coordinates of Any Photograph

Learn how geolocation investigators reverse-engineer photo capture times using shadow trigonometry, sun azimuth calculations, and astronomical solar trajectory modeling.

When metadata has been stripped and timestamps are scrubbed, the sky remains an undeniable witness. Chronolocation enables intelligence analysts to calculate the exact hour and minute a photograph was taken using basic trigonometry, cast shadows, and astronomical solar trajectories.

1. The Fundamental Shadow Trigonometry Equation

To determine the sun's solar altitude angle (\(\alpha\)), you only need two measurements: the physical height of a vertical object (\(h\)) and the length of the shadow it casts on flat ground (\(s\)):

Solar Altitude Angle (θ) = arctan( Object Height / Shadow Length )
Sun Azimuth Bearing (°)  = ( Shadow Direction Heading + 180° ) mod 360°

2. Practical 4-Step Chronolocation Methodology

1. Identify a Vertical Reference Object: Find a light pole, street sign, fence post, or human standing upright on level terrain.
2. Establish True Geographic North: Use street grid orientation, satellite landmarks, or building alignments to calibrate the compass.
3. Measure Shadow Heading & Ratio: Calculate the shadow's cast direction and height-to-shadow ratio.
4. Correlate with Solar Ephemeris: Cross-reference the resulting solar altitude and azimuth curves for the target date to derive the exact capture window.

Interactive OSINT Tool

Geospatial Shadows & Chronolocation Forensics

Calculate solar altitude, sun azimuth bearing, and candidate UTC capture times from shadow measurements.

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Frequently asked questions

What is chronolocation in OSINT?

Chronolocation is the science of determining the exact date, time, and timezone when a photograph or video was recorded using astronomical indicators like sun position, shadows, weather, and seasonal foliage.

How does shadow length reveal time of day?

By measuring the ratio of an object's known height to the length of its cast shadow, investigators compute the sun's altitude angle (tan θ = height / shadow). Comparing this angle to solar trajectory tables pinpoints candidate times.

What is solar azimuth?

Solar azimuth is the compass direction from which sunlight comes. A shadow cast toward the Northeast (45°) means the sun is located directly in the Southwest (225°).

What software tools do chronolocation experts use?

SunCalc, Google Earth 3D sunlight simulators, ShadowCalculator, and Stellarium.

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