Photogrammetry Accuracy Estimate Calculator
An ASSUMED planning range from GSD — kept apart from MEASURED RMSE, bias and residual statistics on independent checkpoints.
Inputs
An ASSUMED planning range from GSD — kept apart from MEASURED statistics on independent checkpoints.
Enter the values and press Calculate.
Or load an example to see a worked result.
Planning bands and measured residual plots appear here after Calculate.
Batch from CSV
One row per calculation, with a header row. Values use the units currently selected in the form above. Up to 10,000 rows; nothing is uploaded.
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter the GSD; the planning multipliers default to an editable 1–2× horizontal and 2–3× vertical heuristic.
- For measured results, enter axis RMSE values or import checkpoints (reference and observed coordinates, or residuals) with explicit column names.
- Only independent checkpoints are accepted; mark any you exclude and give a reason.
- Optionally enter your project RMSE target.
How it works
Planning: GSD × your low and high multipliers — an ASSUMED envelope, not a confidence interval and not a measurement.
Measured: residual = observed − reference; RMSE_E = √(ΣΔE² ÷ n), RMSE_N likewise, RMSE_H = √(RMSE_E² + RMSE_N²), RMSE_Z from the points that have heights. Bias is the mean residual; the standard deviation about the mean is a different figure.
Empirical median and 90th-percentile horizontal residuals use linear interpolation between ordered values. No 95 % figure is derived from an RMSE and no standard-compliance badge is shown.
Worked example
Residuals E ±3 cm, N ±4 cm, Z ±12 cm. RMSE_E = 3 cm, RMSE_N = 4 cm, RMSE_H = √(3² + 4²) = 5 cm, bias 0, largest horizontal residual 5 cm, RMSE_Z = 12 cm. The planning envelope for a 2 cm GSD is an assumed 2–4 cm horizontally and 4–6 cm vertically.
Frequently asked questions
Does a 2 cm GSD mean 2–4 cm accuracy?
Not by itself. The multipliers are a planning assumption; only independent checkpoints that took no part in the adjustment measure accuracy.
Can I exclude outliers?
Yes, by ID with a reason. The original statistics stay beside the filtered ones.
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Cite this tool
Zerdly. (2026). Photogrammetry Accuracy Estimate Calculator. Retrieved from https://www.zerdly.com/tools/photogrammetry-accuracy-estimate-calculator/
Tip: Enter any known values to calculate the remaining results.
Designed to run locally in your browser. Tool inputs are not intentionally stored by Zerdly unless stated otherwise.