Data
Various kind of data were used to carry out this study:
- One vector file showing the different districts of the Vernier municipality with basic characteristics of each district. We resume the ones we used for our study: the number of habitant, the unemployment rate, and the median revenue per household in 2013 (University of Gevena – Faculté des Sciences Economiques et Sociales (CATI – GE).
- One vector file containing the polluted areas listed in the cadastral plan according to the “Loi de protection de la nature – Ordonnance sur la protection des sol” of the Swiss law. Data where aggregated and vectorized directly from the cadastral plan by the “Système d’Information du Territoire de Genène” (SITG).
- One vector file containing the main rivers passing through the territory of Vernier municipality, available on the website of the SITG.
We did several manipulations with these data as creating point file from polygons layers or calculating population density per district to cite few of them
Methods
Having the previous listed data, we used the software QGIS 2.18.3 Las Palmas, a Geographical Information System tool which allow to do a bunch of different operations using vector as well as rater files. We determined the density of population, where for each polygon we divided the population living in it by its area (hab/km2). From the polygon vector file containing the population statistics, we created a point vector file using the centroid tool of QGIS. It allowed us to have a point file with each centroid of each polygon having in its attribute table the same data as in the polygon file. This file allowed us to represent the unemployment rate as well as the median revenue per household (see Fig.8). Then Geoda (a spatial data analysis, geovisualization, spatial autocorrelation and spatial modeling software) has been used to remark and perceive some of the collected data facets. We did thanks to this software some box map and box plot to detect some spatial outliers, and we used the scatter plot tool to study the spatial correlation of different variables under study. The results are presented in the next section.
Results
We first look at basic distribution of principal socio-economic features and the distribution of polluted sites in the Vernier municipality (Fig. 1,2,3,5), then we look into more details about their spatial characteristics and try to link those different vairables (Fig. 4,6,7). Finally, the map summarizing these essential features is presented in Fig. 8.