Factorial analysis applied to landscape metrics defined in FRAGSTATS

A program for spatial analysis based on a grid of pixels (FRAGSTATS 3.0) was used and the results of the analysis of 50 maps of land occupation using this programme were presented. 33 metrics of the landscape's structure were used and the properties of the metrics for various landscapes (maps of land occupation in Continental Portugal) were investigated. The metrics of the landscape's structure describe the size and form of the landscapes, the abundance of each type of spot and the spatial distribution of similar or different spots. To overcome the ambiguity of individual metrics and behavioural pecularities, a varied factorial approach was adopted to describe and compare landscape structures. An analysis of main components for the 33 metrics and 50 landscapes was carried out. The first five factors explain 91.2% of the variation. These factors can be interpreted as an average of compaction of the spot, image texture (distribution of the pixels and proximity), landscape area, number of classes, area–perimeter relation (fractional measures).