Distance/azimuth calculator for 2 latitude and longitude points (great circle/ellipsoid)

Inputs

Tip: No matter which field you paste "Latitude, Longitude" (e.g. 35.6812, 139.7671), it will be automatically split into two fields.

Results

How to use this calculator effectively

This calculator is designed to make scenario checks fast. Use a repeatable workflow: baseline first, one variable change at a time, then compare output direction and magnitude.

How it works

Run your first scenario with defaults. Then, change exactly one assumption and observe which result changes most. That is the fastest way to identify sensitivity and explain what drives the outcome.

When to use

Use this page when you need practical planning support, side-by-side alternatives, or a clean baseline for further discussion.

Common mistakes to avoid

• Changing multiple assumptions simultaneously.
• Confusing percent and decimal inputs.
• Mixing unit systems across scenarios.
• Relying only on rounded display output for final conclusions.

Worked example

Prepare a base case and one alternative case, then compare outputs and validate the direction, scale, and interpretation with the same assumptions across both cases.

See also

• Solar altitude, direction, sunrise/sunset, day length (ES-002)
• Distance to horizon / drop in earth curvature (refraction coefficient k) (ES-014)
• Terrain: Slope gradient (degrees/%), elevation difference, line of sight gradient (ES-005)
• Tidal/diurnal cycle: sunrise/sunset + moon phase + tide (data linkage) (ES-021)

How to use Distance/azimuth calculator for 2 latitude and longitude points (great circle/ellipsoid) effectively

What this calculator does

This page is for estimating outcomes by changing inputs in one controlled workflow. The model keeps your focus on variables, not output shape. Start with stable assumptions, then test sensitivity by changing one key input at a time to observe directional impact.

Input meaning and unit policy

Each input has an expected unit and a typical range. For reliable interpretation, check whether you are using the same unit system, period, and base assumptions across all runs. Unit mismatch is the most common source of unexpected drift in numeric results.

Use-case sequence

A practical sequence is: first run with defaults, then create a baseline log, then run one alternative scenario, and finally compare only the changed output metric. This sequence reduces cognitive load and prevents false pattern recognition in early experiments.

Common mistakes to avoid

Avoid changing too many variables at once, mixing incompatible data sources, and interpreting a one-time output without checking robustness. A single contradictory input can flip conclusions, so keep each experiment minimal and document assumptions as part of your note.

Interpretation guidance

Review both magnitude and direction. Direction tells you whether a strategy moves outcomes in the desired direction, while magnitude helps you judge practicality. If both agree, you can proceed; if not, rebuild the baseline and verify constraints before deciding.

Operational checkpoint 1

Record the exact values and intent before you finalize any comparison. Confirm the unit system, date context, and business constraints. Compare outputs side by side and check whether differences are explained by one changed variable or by hidden assumptions. This checkpoint often reveals the single factor that changed everything.