Bringing Geospatial Analysis to the Social Studies: an Assessment of the City Sprawl in China

International audienceCurrent poster presents an example of Landsat TM image processing using ENVI GIS. Research area: Taipei, Taiwan. Located on the north of the island, Taipei is Taiwan’s core urban, political and economic center; population >2.6 M continuing to expand affecting urban landscapes. Research aim: spatio- temporal analysis of urban dynamics in study area during 15 years (1990- 2005) Research objective: application of GIS methodology and remote sens- ing data to spatial analysis for a case study of Taipei. Data: Landsat TM images taken from the USGS. Software: ENVI GIS. Workflow includes following steps: 1) Preliminary processing 2) Creation color composites 3) Classification using K-means algorithm 4) Mapping using classification results 5) Accuracy assessment. The preliminary data processing includes image contrast stretching, which is useful as by default, ENVI displays images with a 2\% linear contrast stretch. For better contrast the histogram equalization contrast stretch was applied to the image in order to enhance the visual quality. The analysis of landscape changes was performed by geospatial analysis. 2 satellite images Landsat TM were processed and classified using ENVI GIS. Result of classification: areas occupied by different land cover types were calculated and analyzed. It has been detected that different parts of the city of Taipei were developing with different rate and intensity. 3 different residential types of the city were recognized and mapped. The results demonstrated following outcomes: 1) intensive urban development of the city of Taipei; 2) decline of green areas and natural spaces and, on the contrary, increase in anthropogenic urban spaces; 3) not parallel urban development in different districts of the city of Taipei during the 15-year period of 1990-2005