Zerdly

Orthomosaic Deliverable Checklist

Checks drone orthomosaic deliverables for GCPs, overlap, GSD, GeoTIFF, DSM/DTM and accuracy.

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How to use this calculator

Acceptance criteria

Required deliverables

Checkpoints

CP = independent checkpoint; GCP = used in the fit (listed but excluded from accuracy). Residual = measured − reference.

GeoTIFF header check (optional)

Reads only the TIFF header tags (size, pixel scale, tiepoint, CRS keys) from your file, in this browser. Classic TIFF only — BigTIFF is not read. It reports what the file declares; it does not verify accuracy.

Capture and control

Image overlap meets the project plan

Overlap and GSD support processing; they do not prove accuracy.

GCPs surveyed and their CRS recordedcritical

Independent checkpoints kept out of the fitcritical

GSD / flying height consistent with the requirement

Processing evidence

Camera calibration / alignment report reviewed

No holes or blur in the mosaic (evidence noted)

Seamlines and colour balance checked

Surface correctly described as DSM or DTM

Metadata

CRS and height system stated in the filescritical

Resolution / GSD stated

Required deliverables

Orthomosaic GeoTIFF delivered and openscritical

QA report delivered and openscritical

Handover

Accuracy (independent checkpoints)

Unverified — no independent checkpoints entered.

RMSE_H = √(mean(ΔE² + ΔN²)). No 95% multiplier is applied. Overlap and GSD support processing but do not prove accuracy.

Not ready for handover

0 of 12 applicable items assessed (0% complete). Completeness is not readiness.

Blockers

  • No independent checkpoints: accuracy is unverified (not zero).

Critical items not passed

  • GCPs surveyed and their CRS recorded
  • Independent checkpoints kept out of the fit
  • CRS and height system stated in the files
  • Orthomosaic GeoTIFF delivered and opens
  • QA report delivered and opens

Still to assess (12)

  • Image overlap meets the project plan
  • GCPs surveyed and their CRS recorded
  • Independent checkpoints kept out of the fit
  • GSD / flying height consistent with the requirement
  • Camera calibration / alignment report reviewed
  • No holes or blur in the mosaic (evidence noted)
  • Seamlines and colour balance checked
  • Surface correctly described as DSM or DTM
  • CRS and height system stated in the files
  • Resolution / GSD stated
  • Orthomosaic GeoTIFF delivered and opens
  • QA report delivered and opens

Records stay on your device as files you choose to save. The page keeps nothing.

No raster is processed here; evidence is what you enter.

How the method works

Independent checkpoints, not fit control
Illustrative method
Independent checkpoints, not fit controlA residual plot of horizontal checkpoint errors with the RMSE ring, beside the count, bias, RMSE and maximum residual; ground control points used in the fit are shown hollow and excluded.ΔEΔN±4.400 m squareCheckpoints n = 2Bias E +1.5, N +2.0 mRMSE_H 3.536 mMax 5.000 m (CP1)GCPs excluded: 1checkpointGCP (excluded)RMSE_H
Fit-control (GCP) residuals and independent accuracy are different. Two checkpoints with residuals (3, 4) m and (0, 0) m give RMSE_H = √((25 + 0) ÷ 2) = 3.536 m and a maximum of 5 m; the GCP used in the fit is plotted but excluded. Report count, bias, RMSE and maximum separately.

Fixed example values for illustration — not your result.

How to use this calculator

  1. Enter the acceptance criteria — CRS, height system, GSD, horizontal and vertical RMSE — and tick the deliverables the job requires.
  2. Paste checkpoints as CSV (ID, CP or GCP, measured E N Z, reference E N Z) and mark each QA item with its evidence.
  3. Read the accuracy summary and the handover decision, then download the QA ZIP.
  4. The residual plot shows each checkpoint's horizontal error with the RMSE ring (GCPs hollow and excluded). Optionally pick the orthomosaic GeoTIFF to read its header — size, pixel scale and declared EPSG code — without uploading or decoding the image.

How it works

Accuracy uses independent checkpoints only: GCPs used in the fit are listed but excluded. RMSE_H = √(mean(ΔE² + ΔN²)), with RMSE_E, RMSE_N, RMSE_Z, mean bias and the largest residual reported. No 95% multiplier is applied.

With no independent checkpoints the accuracy is unverified — never a zero RMSE. A required deliverable that is not delivered, or an RMSE over the criterion, blocks handover even when every item is assessed.

Overlap and GSD support processing but do not prove accuracy, and the surface should be called a DSM or DTM honestly. No raster is processed in the page.

Worked example

Two checkpoints. Residuals (3, 4) and (0, 0) m give RMSE_H = √12.5 = 3.536 m and a 5 m maximum. If those points were GCPs, there would be no independent accuracy result at all.

Frequently asked questions

Why keep check points separate from GCPs?

GCPs are used to georeference the model; independent check points are held back to measure the true accuracy of the result. Using all points as GCPs leaves nothing to verify it.

Is this official course material?

No. It is free study support mapped to surveying course levels — not official North Metropolitan TAFE content or advice. Always follow your lecturer and the official assessment brief, and check your own working.

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Cite this tool

Zerdly. (2026). Orthomosaic Deliverable Checklist. Retrieved from https://www.zerdly.com/tools/orthomosaic-deliverable-checklist/

Tip: Enter any known values to calculate the remaining results.

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