RTK Shadow Height Estimator

Enter two RTK rover coordinates — where the subject was standing and where the tip of their shadow falls — along with the date, time, and time zone. The tool computes solar elevation using a NOAA-standard algorithm, calculates shadow length via haversine distance, and derives estimated height.

HOW IT WORKS

Shadow length is computed from the haversine distance between the two RTK points. Solar elevation is calculated from the NOAA equation-of-time model using the base point's latitude, longitude, date, and local time. Estimated height = shadow length × tan(solar elevation).

POSTURE CORRECTION

A 1–10 posture scale accounts for subjects who are not standing fully erect. 10 is military-bearing upright. Each step down applies a correction factor — the tool divides the raw shadow height by that factor to recover the estimated true standing height. Posture 1 (lying flat) is flagged separately; standard shadow geometry does not apply and the result is an approximation only.

RTK ACCURACY AND ERROR PROPAGATION

Enter your receiver's horizontal accuracy (1σ, in cm). The tool computes combined shadow-length uncertainty as √2 × σ_RTK (two independent points), propagates it through the height formula, and displays ±1σ (68%) and ±2σ (95%) confidence intervals with a full 95% range.

Typical fixed RTK: 1–3 cm. Float or degraded solution: 5–30 cm. Check your rover's specification sheet and solution status before recording accuracy.

TIME ZONES

UTC plus all U.S. standard and daylight time zones, Arizona no-DST, Alaska, Hawaii, Chamorro, and Philippine Standard Time.

—

LEGAL DISCLAIMER — READ BEFORE USE

This tool is a field calculation aid for preliminary investigative and planning purposes only. It is not a certified survey instrument, not a forensic measurement tool, and not a substitute for analysis by a licensed professional land surveyor or forensic expert.

Results depend on RTK solution quality, correct time zone selection, accurate shadow tip identification, and the user's judgment of subject posture. The solar position model is an approximation (NOAA equation-of-time method, typical accuracy ±0.1°–0.3° solar elevation). No warranty of accuracy, fitness for any particular purpose, or admissibility in any legal proceeding is expressed or implied.

Any use of this tool in a law enforcement, legal, or regulatory context must be reviewed, verified, and certified by a licensed land surveyor or qualified forensic professional before being presented as evidence or relied upon for official determinations. The developer, G2G Simulations / TropicOceanic, accepts no liability for decisions made based on output from this tool.

Use of this tool constitutes acceptance of these terms.