AN ENVIRONMENTAL MONITORING OF THE HANG ZHOU AREA 
BY LANDSAT DATA 
by 
ZHI-PENG ZHANG 
and 
GUAN-HUA XU 
Chinese Academy of Forestry 
Wan Shou Shan, Peking, China 
Abstract 
This paper discusses the results of the environmental 
monitoring over the Hang Zhou area, based on visual and 
computer assisted interpretations of landsat MSS data. 
The study area covered the city proper of Hang Zhou 
and its suburbs, with parts of forested and agricultural 
lands, lakes and rivers included. The city of Hang Zhou 
has been expanded during thepast thirty years. Land 
uses in its suburbs are of a mixed pattern, like those 
in most other Chinese cities. Many overmatured forests 
were cleared and subsequently converted into new 
agricultural or reforested lands. The agricultural lands 
aro now divided into small patches by differenti crops. 
The new unSupervised classification method, which 
combines spactral information with spatial information, 
was used for digital image classification. The false 
colour composition images were used for visual inter- 
pretation. The accuracy of classifications was compared 
with ground truth obtained from the aerial photography. 
It has been shown that by using the new unsupervised 
classification method it is generally possible to get 
monitoring of urban growth, forest damage and the 
silting up of rivers and laxes for conplicated land-use 
patterns. The accuracy of computer classification tends 
to be greater than that of visual interpretation. 
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