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Forestry
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Analysis of function of forest using artificial satellite data and geographical information
Subject area of investigation
In present study, we selected and made analysis on Sapporo City which is the central city in north part of Japan (fig.1). Sapporo is the largest city following Tokyo, Osaka, Nagoya, etc and has the most abundant green among these large cities. The urban district spreads over the plain land, and the forest area called Satoyama is located as if to surround the. The forests in Satoyama its located as if to surround the city. The forests in Satoyama area hold important position as the green are abutting on city playing an important role in forming the full-of-green of Sapporo city.
Fig. 1 Studt area
The data used for the study
- MSS CCT (PATH 116 -Row 030 , Aug.29.1972 )
TM CCT (PATH 108 -ROW 030 , Sep.11.1985 )
- Altitude data file (1982), vegetation data file (1984),
River basin data file (1984), geological map (1/50,000, 1946-1950),
Soil map (1/200,000,1975)
Method of analysis
The analysis procedures are as shown in fig.2.
- Grasping of regional characteristics of study area
For the purpose to grasp the regional characteristics of study, we made land cover classification using LANDSAT TM data, and grasped present state of distribution and secular change of the forest. We also grasped the geographical characteristics by collecting data of topography, geology, soil and climate.
- Study on the functions to be analyzed and establishment of analysis standard
We discussed the functions to be analyzed in this study based on the present state of forest and regional characteristics grasped in (1) above. We also established the analysis standard referring to past analyses already performed in Japan.
- Construction of image database
The basic data of for analysis were converted into image database of the uniformed pixel size 100m x 100m, and stored into disk. The map data such as geological map and soil map were digitized by using scanner. The data field of altitude data, vegetation data and river basin data were converted into image by calculation and compiled in a database. The topographic data were analyzed by using altitude data, and slope aspect, slope, relief volume were obtained as image data. The images of present state of forest obtained from TM data were re-sampled in a manner so that the pixel size would be 100m x 100m and compiled in a database.
- Analysis of forest function
Analysis of forest function was performed by the overlay of images based on the analysis standard. The analysis results were compared and checked with the present, state and if contradiction was found thereon, the analysis standard was reviewed, and analysis was performed again.
- Grasp of forest characteristics
The characteristics of forests around Sapporo city were grasped by the forest function individually grasped as well as by comprehensive analysis.
Fig. 2 Method of analysis
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