抄録
Ten thousand scale vegetation maps are necessary to evaluate and analyze the urban environment, since vegetation can affect urban environment on thermal aspects. As a method for constructing the vegetation cover map, the vegetation cover ratio in a pixel using the index is thought as convenient method for estimating the small scale vegetation in urban areas. This study aimed to find out an index in order to assume the vegetation cover ratio in a pixel in urban areas.
The relationships between vegetation cover ratio in a pixel and conventional vegetation indices, NDVI, RVI and SRVI, were numerically analyzed. The relationships between those were analyzed by the material combina-tions of the simple urban surfaces, which have vegetations, tree and lawn, and non-vegetations, concrete, soil, asphalt, roof tile, aluminium and tile. The results shown the possibility that the estimation accuracy of vegetation cover ratio in a pixel may be unbalanced according as amount of the vegetation cover ratio in a pixel and as characteristics of the site. On that reason, we proposed a new index, modified ratio vegetation index (MRVI), which have three concepts of index for extract the vegetation cover ratio in a pixel in urban areas, adaptable to general satellite data, approximate by linear calibration, small assumption error. The efficiency of MRVI was proved by the material combinations of the simple urban surfaces and also simulation MSS data with several spatial resolutions.
