Skip to content

Photogrammetric Documentation Workflow (Metashape)

1. Import Images

Create a directory named with the acquisition date (e.g. 2018_08_04).

Inside this directory, create a project directory named according to the trench and context number, for example:

  • PAP_T_II_154
  • MAL_TT_IV_186_187

Within the project folder:

  • store all photographs intended for photogrammetric processing in an img subdirectory,
  • store additional documentary photographs separately.

Directory

2. Save the Project

Save the Metashape project using the following naming convention:

MAL/PAP_trench_context.psx

Example:

PAP_T_VI_520.psx

3. Assess Image Quality

Run: Tools → Estimate Image Quality...

Review a few images with the lowest quality values and identify blurred or problematic photographs.

Show Screenshot Hint Estimate Image Quality

4. Align Images

Run: Workflow → Align Photos...

Recommended settings:

  • Accuracy: High
  • Pair Preselection: Disabled
  • (Advanced) Key point limit: 40 000
  • (Advanced) Tie point limit: 4 000
Show Screenshot Hint Align Images

5. Verify Camera Alignment

Inspect the sparse point cloud and camera positions.

Confirm that:

  • camera alignment is correct,
  • image orientation is logical,
  • no misaligned cameras are present.

6. Detect Markers

Run: Tools → Markers → Detect Markers...

Recommended settings:

  • Marker Type: Cross (non-coded)
  • Tolerance: 10 (or higher if necessary)
  • Maximum residual (pix): 3 (or higher if necessary)
Show Screenshot Hint Detect Markers

7. Assign Marker IDs

Review detected markers and assign the correct marker identifiers.

Show Screenshot Hint Filter Images Filter Images

8. Import Control Point Coordinates

Import the coordinate file containing the surveyed marker coordinates.

9. Complete Missing Marker Measurements

If any markers were not detected automatically, manually place marker projections on the relevant photographs.

Show Screenshot Hint Projections on Images

10. Check Georeferencing Accuracy

Verify the marker residuals and overall georeferencing quality.

A Total Error of approximately 1 cm (0.010 m) or less is generally acceptable for archaeological documentation.

Show Screenshot Hint GCP Accuracy

11. Generate Point Cloud

Run: Workflow → Build Dense Cloud...

Recommended settings:

  • Quality: Low
  • (Advanced) Depth filtering: Mild
Show Screenshot Hint Build Point Cloud

12. Inspect the Dense Point Cloud

Check the dense point cloud for:

  • gaps,
  • areas with insufficient coverage,
  • reconstruction artefacts.

13. Define the Reconstruction Region

If necessary, adjust the bounding box using:

Resize Region and Rotate Region

Limit the processing area to the archaeological feature or context being documented.

14. Build the Mesh

Run: Workflow → Build Model...

Recommended settings:

  • Source data: Depth maps
  • Quality: Low
  • Face count: Medium
Show Screenshot Hint Build Model

15. Inspect the Mesh

Review the mesh geometry and verify that:

  • the reconstructed surface accurately represents the archaeological context,
  • no significant artefacts are present.

16. Build the Texture

Run: Workflow → Build Texture...

Recommended settings:

  • Texture type: Diffuse map
  • Source data: Images
  • Mapping mode: Generic
  • Blending mode: Mosaic (default)
  • Texture size: 4096
  • Page count: 1
Show Screenshot Hint Build Texture

17. Verify Texture Quality

Inspect the textured model and check for:

  • blurred areas,
  • texture seams,
  • colour inconsistencies,
  • missing texture coverage.

The project is now ready to be saved for later (automatic) recomputation and export as archaeological documentation.