Helsingin sosioekonominen erilaistuminen : tapauksena asemanseudut

The aim of the thesis was to study the socioeconomic structure of Helsinki and bring new and relevant information to the discussion about the future of the Helsinki region. Socioeconomic differentiation in Helsinki is a widely studied subject. The focus, however, has mostly been on statistical region or grid cell based analyses. In this study the socioeconomic structure was, for the first time, linked with transport nodes. Train and metro station areas are in Helsinki often functional and commercial centers of their districts and as transport nodes they offer good connections to rest of the region. In this study the train station areas were defined as areas within a 600 meter radius buffer from the train/metro platform. Socioeconomic structure was defined by four independent variables: percentual amount of highly educated population (= university or applied university diploma), employment rate, median income of the workforce and the percentual amount of population with first language other than Finnish or Swedish. Values of the station areas were set against the values of the whole city as well as against the values of Helsinki's districts and major districts and the values of the surrounding 300 meter zone of the station area itself. The station areas were divided into quartiles based on their rank within each variable. These quartiles were then used to create a combined categorization which shows the relative socioeconomic level of each station area when compared to the surrounding city. The data of the thesis comprised of large amount of GIS data from several different places. The most central data was from SeutuCD'09 by Helsinki Region Environmental Services Authority HSY and from Ruututietokanta grid database provided by Statistics Finland. In addition to the two focal data sources also some GIS data by the city of Helsinki's planning and real estate departments was used. Station areas were categorized in the thesis in two separate ways: based on functionality and on the diversity of built environment. In order to measure the diversity of the built environment an application was created that used Simpson's diversity index used mostly in biological studies. Urban diversity has not been widely studied in terms of GIS data based indexes before. Socioeconomic differentiation can be clearly noticed in Helsinki's station areas. Some station areas are clearly socioeconomically strong regions where as some station areas, especially in the lowest quartile, are showing worrying results. The findings reflect earlier research results about the socioeconomic differences within Helsinki. The station areas with lowest values are located mostly in eastern, northeastern or northwestern parts of Helsinki, where as the station areas with highest values are generally located either in downtown or in the region between the urban core and the apartment building suburbs built in 1960's and 1970's. Regardless of the comparison level proximity to the station appears to have negative impact on the socioeconomic level of an area. Distance to the city center correlates with the socioeconomic situation of a station area. The closer the station is to the urban core, the higher the socioeconomic status. When comparing the relative socioeconomic status of the station areas to surrounding urban regions, the station areas with highest relative status are located in the region between the city center and the furthest suburbs and have been inhabited for a relatively long time. Recent development shows that the station areas with slowest growth rates or even declining rates are mostly the ones that have already been areas of low socioeconomic status. The results corroborate earlier findings about the linkage of subsidized and owner-occupied housing to the socioeconomic structure of a given region. In case the goal is to maintain the socioeconomic balance of Helsinki the ownership of new housing plays a crucial role in preventing the segregation development.