Characteristics Analysis of Water Body in Tidal land Reclamation Area using Landsat TM Image data
4.Methodology
The values of CCT count were investigated for each band of Landsat TM data in the firest place to examine the characteristics of band data using two kinds of satellite images data taken in different times. Composite color images were generated using band 3 ( red ), band 2( green ) and band 1( blur ) respectively . these bands are available to interpret outflow pattern and the phenomenon of water area for band 1, to examine spectral characteristics for band 2 and to an analysis f water turbidity for band3 . these images explain the state of freshening process n the freshening reservoir constructed through tided reclamation project.
The IBASYS software, a kind of image processing system operating on the workstation of Remote sensing/GIS laboratory at Ibaraki University was used to perform geometric correction and unsupervised classification . the areas which include Yongsan river 2nd and 3rd stage district were cut out on 1024 lines by 1024 pixels form each full scene of the original Landsat TM data. The CCT count is examined respectively on the study area of 768 lines by 768 pixels after geometric correction using these images. Eight ground control points were selected form the topographic map of 1:50,000 scale ( fig .4.1) the absolute difference between calculated and measured values of the image coordinates was kept down within 1 pixel. Affined transformation was used for images coordinated corresponding to topographic coordinates.
Fig. 4.1 Location of selected of GCPs
The spectrum characteristics of the image data was examined through the CCT count of each category for land cover and each band. The CCT count of each Band was investigated at 3 places in sea, and 6 places in freshening reservoir along the center line of the sea and freshening reservoir, as shown in fig. 4.2. the standard point is the center of the enclosure dike in the freshening reservoir. The values of CCT count for land cover classified into six categories were used the mean values acquired at 3~6 places for each category.
Fig. 4.2 Composite color image of study area [Sep.22,1992] and survey points of the CCT count
5. Resutl and Discussion
The present study investigated spectrum characteristics for each band data on Yongsan river 3rd stages with two satellite images data acquired on different days and field survey, and at the same time, examined the state of the progress of the construction works.
Fig 4.2 shows the situation the enclosure dike completed in Yongam lake and under construction in kum lake. But, in Fig. 4.3, the enclosure dike of Kum lake is also completed and the drained tidal flats are whitened by salt educing on the ground.
Fig. 4.3 Composite color image of study area [Sep.28,1994]
The freshening process of water area shows the other state, as shown in fig.4.2 that is, Yongsan estuary lake is in completed situation. Yongam lake is under progress, and Kum lake is formatting the same pattern as sea. However, fig4.3 shows the state completed for Yongsan estuary lake and Yongam lake, and under progress for kum lake.
Fig.5.1 shows the value of CCT count for land cover in Yongam lake in Yongsan river 3rd stages. While the variance of sea water and fresh water is hardly shown in the image data of 1992, the images data of 1994 shows a few variance for band1,2 and 3.
Fig. 5.1 CCT count for land use of Yongsan river 3rd stages
Fig,5.2 CCT count of Yongam lake districtshows the value of CCT count examined for sea water and fresh water along the center line of yongam lake. The images data of 1992 does not show the variance of sea water an fresh water but the 1994 data shows the variance for band1,2 and 3, for the upstream of freshening reservoir. These data show those are few the difference of shades between fresh water from the enclosure dike to the center of Yongam lake and sea water.
Fig. 5.2 CCT count of Yongam lake district
Fig.5.3 is the value of CCT count in Kim lake, under condition mentioned above. It shows the same pattern as in Fig.4.2. the value of CCT count for sea water and fresh water is the same because the enclosure of Kum lake is incomplete. The values of band1, 2 and 3 also shows the variance.
Fig. 5.3 CCT count of Yongam lake district
Fig .5.4,5 are the images classified by the ward method of the unsupervised classification methods of the land cover classification. In the these images, while a body of water in the freshening reservoir is not shown, the situation of freshening process is classified clearly.
Fig. 5.4 Unsupervised classification image [Sep.22, 1992]
Fig. 5.5 Unsupervised classification image [Sep.28, 1994]
6. Conclusions
The study examined spectrum characteristics for each band land cover on comprehensive agricultural development project for Yongsan river watershed 3rd stages progressing in Korea now. And, the classification images based on the values of CCT cont were generated. As a result an analysis of water area including sea water and fresh water can investigated by using Landsat TM data. Of the data, especially band 1,2 and 3 are applicable to the analysis of the shades and water quality in the freshening reservoir. And, it was also shown fundamental knowledge to extract more detailed information.
References
-
Choi,M.S.,T. Hoshi: Analysis of water area pattern on Youngasangang 3rd stages, Proc of Annual Conference of JSPRS, 1-4,pp203~206, 1997.
- Torii K., T. Hoshi, B.J.Cho, D.W.Kang: Application of satellite Images Data to Tideland Reclamation Project in Southwestern Coastal Zone of Korea, Proc. Of the 14th ACRS,B-4-1 ~6.1993.
- Torii K., T. Hoshi et. Al.: Investigation on Tidal Land Reclamation in Korea Using Satellite image Data, proc.of the 17th ACRS, G-4-1~6. 1996.
- Kazuhiro SATO, Dwi Setyono, saw Eh DAH structure of satellite data for mangrove Area in Okinawa (1) - Structure of TM data of Landsat 5 for Mangrove Area in Iriomote Island Proc. Of the 14th ACRS, E-3-1~6,1993.
