Interpretation and applications of the Slar imagery of Shanghai suburbs

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Interpretation and applications of the Slar imagery of Shanghai suburbs

Interpretation of Slar iamges
Shanghai area is located in front of deltaic plain of Yang-zi River. The lerrian is flat and ri-vers are very dense. Exploitation and use of this area are much earlier. The flying areas of various crops amall and intensively cultivated. The test region described by this paper is from the Shanghai Oil and Chemical Factory on the west to Nan Hui Mouth of Nan Hui Country on the east, covering a seacoast of about 70 Km long, the remote sensing area is about 300 Km2. The area interpreted in this paper is typically selected from xin Huo State Farm of Fen Xian Country including prawn-reising pools, fish pools, cow fields, farmer's houses, cct. The ratio of use is high and reflects comprehensive development is farming, stack raising, fishing and rural industry.

Table 1. The density change of slar imagery with ground influence factors

Land Mass Name	Density	Description	Influence factor for Slar echo
Wheat fields	1.25	Growthing stage, H=29, 4cm, LA I=30	Roughness and dielectric constant of wheat
Green manure (Alfalfa)	1.10	Cover rate=64% for green manure, H30cm, LAI=1.8 other are weeds.	Less roughness and dielectric constants
Rape fields	1.35	Cover rate=100%, H=37,. 45cm, LAI=4.6	Higher roughness and dielectric constants
Simple Constructed highway	1.30	Soild surface, with weeds along two sides, 4m width, along by rivers	Rivers and roads are specular reflector with rough weeds bands and its dielectric
Farmer's houses	1.46	Dispersing and closing the roads	The houses and ground act as a corner refectro
Play ground	1.02	Cement ground surface	Specular reflector
Factory and Residential areas	1.59	Bigger Factory buildings and two to three floors houses.	The houses and ground act as a corner refector and surrounding matter scatter radar signal
Rivers	0.77	20-40m width, stretching as lien, lush weeds on the banks	the water surface act as specular reflector and seeds scatter radars signal
Sea	0.74	Very vast and calm	Specular reflector
Fish polls	0.96	Rectangle form, rougher soil raod between two pools	Water act as specular reflector and ground scatter radars signal
Swamp	1.54	Hard sand as rock and high moisture	The roughness of swamp and higher humidity
Fruit grove	1.19	Not growthing leaves	The roughness and dielectric constant of branch
Digging fish pools	1.33	The p[arts are water, the other are soil and breaking stone	The refection and scatter of water, soil and stone
Iron Ship	1.58	Anchored on seabeach for breaking up	The metal has strong reflection feature
Jetty	1.54	Extending toward to sea, piled with stone very rough	The ground has larger roughness and acts as the corner reflector

We measured quantitatively the densities of various surface objects and scene on these SLAR pictures, then processed pictures with image enhancement, edge enhancement, smothing filtering and pseudocolour processing on computer system. In order to further analyse the variation and relationships of different earth image features, we referred to colour infrared photographs and latest maps, carried out practical survey simultaneously. We collected various data regarding land and crops, finally summerized the relationships among variation of radar image density and eart5h influence factors which has general significance listed in table 1.