On Shape Metrics in Landscape Analyses Vít PÁSZTO Department of Geoinformatics, Faculty of Science, Palacký University in Olomouc Reg. č.: CZ.1.07/2.3.00/
Presentation schedule Introduction Data used Study area Methods Case study 1 (Results) Case study 2 (Results) Case study 3 (Initial idea) Conclusions
Introduction Computer capabilities used by landscape ecologists Quantification of landscape patches Via various indexes and metrics Prerequisite to the study pattern-process relationships (McGarigal and Marks, 1995) Progress faciliated by recent advances in computer processing and GIT
Introduction Shape and spatial metrics are exactly those methods for quantitative description In combination with multivariate statistics, it is possible to evaluate, classify and cluster patches Available metrics were used (as many as possible) Unusual approach in CLC and city footprint analysis
Methods - Shape & spatial metrics Fundamentally based on patch area, perimeter and shape Easy-to-obtain metrics & complex metrics Software used: o FRAGSTATS 4.1 o Shape Metrics for ArcGIS for Desktop 10.x EXAMPLE/EXPLANATION
Methods - Shape & spatial metrics
Methods - Shape & spatial metrics
Methods - Shape & spatial metrics
Methods - Shape & spatial metrics
Methods - Shape & spatial metrics Convex hull Detour index
Case study 1 - Data Freely available CORINE Land Cover dataset: o 1990 o 2000 o 2006 Level 1 of CLC - 5 classes: o Artificial surfaces o Agricultural areas o Forest and semi-natural areas o Wetlands o Water bodies
Case study 1 - Study area Olomouc region (800 km 2 ) - 1/2 of London More than 944 patches analyzed
Case study 1 - Methods Principal Component Analysis (PCA) for consequent clustering Cluster analysis: o DIvisive ANAlysis clustering (DIANA) o Partitioning Around Medoids (PAM) Software - Rstudio environment using R programming language
Case study 1 - Workflow Diagram CLC (1990, 2000, 2006) Metrics calculation PCAClustering DIANA PAM
Case study 1 – no. of clusters
Results – DIANA clustering Hierarchichal clustering Tree structured dendrogram One starting cluster divided until each cluster contains one single object
Results – DIANA clustering
Results – Diana clustering
Results – PAM clustering Non-hierarchichal clustering „Scatterplot“ groups Using medoids Similar to K-means More robust than K- means
Results – PAM clustering
Results – PAM clustering
Case study 2 - Data Urban Atlas: o Year 2006 o Only Artificial surfaces o Digitized to have urban footprints o All EU member states capital cities
Case study 2
Fractal Dimension Index Bruxelles (1.0694) Vienna (1.1505) Cohesion Index Bruxelles (0,948875) Tallin (0,636262) Results
Results Elbow diagram (no. of clusters):
Results – DIANA clustering
Results – PAM clustering
Results
An idea (to be done) Church of st. Maurice Case study 3 – what about cartography
Case study 3 – what about cartography
Case study 3 – what about cartography
Conclusions & Discussion Shape Metrics are useful from quantitative point of view Tool for (semi)automatic shape recognition via clustering Double-edged and difficult interpretation Strongly purpose-oriented Geographical context is needed Input data (raster&vector) sensitivity
Conclusions & Discussion Not many reference studies to validate the results Shape metrics correlations There is no consensus about shape metrics use among the scientists Proximity and Cohesion index – for centrality analysis Fractal dimension, Perim-area, Shape Index – for line complexity evaluation
The End Vít PÁSZTO On Shape Metrics in Landscape Analyses