The influence of the spatial assessment unit on the final outcome of the geodiversity value

Recently, noteworthy advancements in geodiversity studies have emerged, due to the capabilities provided by Geographic Information Systems (GIS) and increasingly accurate digital data from diverse sources. New methods of geodiversity assessment have been proposed and research on validating aggregated geodiversity ratings has emerged. Thus far, scant consideration has been given to selecting the suitable shape and size for the spatial assessment unit. This conference paper presents the outcomes of a study investigating the impact of the shape and size of primary spatial assessment unit on the final map of geodiversity. Additionally, the reliability of the assessment was evaluated through spatially explicit uncertainty analysis (UA) for three national parks in Poland representing one of three morphogenetically different landscape types: mountains, uplands, and lowlands.

The geodiversity assessment was based on global and local spatial multicriteria analysis (Weighted Linear Combination and Local Weighted Linear Combination). As part of the approach, the assessment input data, comprising geodiversity factor ratings and weights, were obtained through crowdsourcing. A GIS-based web application called the geo-questionnaire was used to collect data from Earth science expert volunteers. The study was conducted for three national parks in Poland – Karkonosze National Park (KNP), Roztocze National Park (RNP), and Wolin National Park (WNP). For each of the parks, the averaged ratings from respondents were aggregated across four selected primary assessment units, namely watersheds, geomorphological features, and grids in two dimensions: 100 x 100 m and 1 x 1 km. For each map, uncertainty analysis was conducted to account for the influence of inputs on the variability (uncertainty) of the model output. As a result, four classes were calculated representing categorical outcomes for geodiversity and its uncertainty. The evaluation of the selected primary assessment units refers to the percentage of the study area characterised by the most desirable result - a relative high geodiversity and low uncertainty, in comparison to the class of relative low geodiversity and low uncertainty.

Shape and size of the spatial assessment unit can significantly impact the final result of the assessment and, consequently, limit the practical applicability of the resulting maps for managing protected and conserved areas (PCAs). In the case of KNP, the selection of watershed as a basic unit proved to be unfortunate. Due to the transboundary nature of the park and constraints related to obtaining consistent data for the entire Karkonosze massif, delineated watershed boundaries do not accurately reflect reality. The Polish part of the park covers the northern slopes of the Karkonosze Mts., which also influenced the elongated shape of many units. The use of grids as the basic assessment units in geodiversity analysis did not show significant differences in this regard for any type of the studied landscapes.