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Multi-Sensor Image Fusion for Urban Expandsion of Chiang Mai City
 Fig. 3. SPOT-1 image panchromatic, 10m resolution.
 Fig. 4. IRS-1D image panchromatic, 5.8m resolution. 2.2 Other related Information Topographic maps which were produced by the Royal Thai Survey Department and an existing land use map from Land Development Department at a scale 1:50,000 were used for supporting image interpretation. 3.Methedology The simple image pre-processing was carried out including image enhancement, the higher resolution image is used as the reference to which the lower resolution image is geometrically registered and Pan-sharpening (the combination of SPOT panchromatic image data, having a spatial resolution of 10m, with Landsat-5 Thematic Mapper images, having a spatial resolution of 30m in year of 1988 and the combination of IRS-1D panchromatic image data, having a spatial resolution of 5.8m, with Landsat-7 Enhance Thematic Mapper images, having a spatial resolution of 30m in year of 2002.). At this stage, Pan-sharpening images can provide a hybrid image having a good spatial detail for the visual interpretation of 1: 50,000 scale, and also ground truth data which were collected by using GPS tracking in 2002 can be used for this step. Urban land use map of 1988 and 2002 were obtained by using GIS to detect urban land use change.  Fig. 5. Pan-sharpening image from Landsat-7 with IRS-1D 4. Results The pan-sharpened image as shown in Figure 5 provided a better interpretation capability for urban land use mapping. Land Use categories were derived from visual interpretation. The image interpretation keys used to identify includes tone, texture, pattern, shape and association. The land use types were divided as 27 class, after that group for reduce diversity of class into 5 classes in Table 4.The land use of 1988 and 2002 as will as the land use detection are shown in Figures 6-8. |