Geodiversity Calculator v2.1 – Documentation

1. Purpose

The Geodiversity Calculator v2.1 is a QGIS plugin designed to calculate spatial geodiversity indices on a regular grid. It integrates geological, pedological, geomorphological, mineralogical, palaeontological, and hydrographic information into comparable subindices and produces a final geodiversity map.

Version 2.1 improves robustness, performance, and usability while preserving the original methodological design.

The plugin is intended for research, teaching, and applied geodiversity assessment, with a focus on transparency, reproducibility, and cartographic usability.

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2. Input data

2.1 Boundary layer
- Polygon vector layer
- Defines the spatial extent of the analysis

2.2 Thematic layers
- Geological units (polygon)
- Pedological units (polygon)
- Digital Elevation Model (DEM) (raster)
- Hydrography
  - Stream network (Strahler order derived internally)
  - Lakes / water bodies (polygon)
- Mineralogical occurrences (point)
- Palaeontological occurrences (point)

All spatial data should be provided in a projected CRS (meters).

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3. Grid creation

3.1 Grid geometry
- Rectangle (TYPE = 2)
- Diamond (TYPE = 3)
- Hexagon (TYPE = 4)

For diamond and hexagon grids, v2.1 applies a minimal, spacing-aware extent expansion to ensure full boundary coverage.

3.2 Grid spacing
Spacing can be entered manually or automatically suggested based on boundary area using explicit area intervals (km²).

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4. Subindex calculation

Geological and pedological subindices are calculated using pure vector-based “any-touch” logic. A grid cell counts a unit if it intersects or touches a polygon.

Geomorphological subindex is derived from DEM using geomorphon classification.

Hydrographic subindex is computed as the sum of maximum Strahler order and lake presence.

Mineralogical and palaeontological subindices are based on point-in-polygon counts.

Temporary helper fields are removed once no longer required.

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5. Optional normalization

Subindices can be normalized to a 0–1 range by dividing by their maximum values. When enabled, normalized fields and a summary field (N_sum) are added.

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6. Output behavior

The final geodiversity grid is always written to disk and added to the QGIS project.

Intermediate layers:
- Unchecked (default): intermediate layers are computed but not opened in QGIS; temporary outputs are used.
- Checked: all intermediate layers are opened in QGIS.

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7. Styling

Final output is styled automatically using graduated colors, Jenks classification, and a Reds color ramp.

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8. Performance and stability

Version 2.1 improves performance through reduced disk I/O, optimized spatial queries, improved grid coverage, and reduced UI overhead.

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9. Typical workflow

1. Load datasets
2. Select boundary
3. Choose grid geometry and spacing
4. Optional normalization
5. Optional opening of intermediate layers
6. Run calculation
7. Inspect final grid

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10. Notes and limitations

- Large areas may require coarse grids
- Data quality strongly influences results
- Original geometries are not modified
