An open-source tool for automated geodiversity assessment

Geodiversity assessment is a key element of geoconservational activities. It reveals the variety of earth scientific features of the examined areas highlighting the zones that may be further analysed for scientific and tourism purposes. Many countries and researchers have already developed assessment methods, which were usually common in using specific geological, pedological, geomorphological, mineral, and palaeontological data sources to calculate a geodiversity index of an area unit (usually a grid cell). In preceding studies [e.g., 1, 2] evaluators used country specific and globally applicable data that can be used in many areas of the world. Although high-detailed assessments require country specific datasets, the use of global sources ensure that the different assessments are comparable to each-other.

In this study an open-source method is proposed to carry out geodiversity assessments automatically with proper base data all over the world. We have developed a QGIS plugin called ‘Geodiversity Calculator’ – an ‘extension’ script in Python for the software. The workflow follows the method developed by Pereira et al. (2013) and consists of 4 steps:

• creates a grid network over the evaluated area with appropriate size in which all thematic data are examined (required: polygon boundary layer);
• evaluates the vector-type geological and pedological data (required: geological and pedological polygon layers in shp format with attributes);
• calculates the geomorphological diversity from a DEM (Digital Elevation Model) applying the geomorphon-method and the Strahler order calculation of the modelled stream network (required: a DEM with adequate resolution);
• evaluates the mineralogical and palaeontological elements (required: point features).

With the evaluation of these thematic layers, a grid of the summed subindex values can be produced. The resulting geodiversity index is similar to the manually produced one: it is available in a spatial database (in gpkg format by default) altogether with all subindices to all grid cells. The process is much faster applying the plugin, but its speed depends on the extent of the area and the base data scale. All partial results are saved to separate files - these can be also visualised and analysed. For validation purposes, the method was also applied on a previously manually evaluated sample area – the Bakony–Balaton UNESCO Global Geopark, Hungary – and successfully reproduced the same index results. Although the tool still needs to be tested on more sample areas and scales, the method could contribute to a better comparability of international assessment results and facilitate geoconservational and geotourism management work.

MP was supported by the ÚNKP-21-3 New National Excellence Program of the Ministry for Innovation and Technology from the source of the National Research, Development and Innovation (NRDI) Fund. GA was supported from the NRDI Fund of Hungary, financed under the Thematic Excellence Programme TKP2020-NKA-06 funding scheme.

[1] Pereira, D.I., et al. (2013): Geodiversity assessment of Paraná State (Brazil): An innovative approach. Environmental Management, vol. 52, pp. 541–552. DOI: 10.1007/s00267-013-0100-2

[2] Pál, M.; Albert, G (2021): Refinement Proposals for Geodiversity Assessment—A Case Study in the Bakony–Balaton UNESCO Global Geopark, Hungary. ISPRS Int. J. Geo-Inf. vol. 10, 566. DOI: 10.3390/ijgi10080566