Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986 
419 
The application of remote sensing technology to natural 
resource investigation in semi-arid and arid regions 
Ding Zhi 
Institute of Xinjiang Biology, Pedology, and Desert, Academia Sinica, China 
ABSTRACT: This paper is to clarify the method, principle, foundation, and results newly ob 
tained in terms of aerial and satellite remote sensing techniligy, which was used for the 
inve stigation of natural resources, such as forest,pasture, vegetation, soil and reeds in 
the mountains and the marshlands regions. Finally, mapped with a scale of 1:50‘,*000. TVio ac _ 
couracy of these maps were tested to be 92.3%. 
1 Introduction 
Xinjiang is located in an arid and semi-arid 
area. Thus, it is easy to collect remote sen 
sing materials of better quality. Applying 
remote sensing technology in this region to 
investigate the natural resources fully de 
monstrates its superiority. In the past few 
years, we have utilized aerial and satellite 
sensing to investigate the mountainous re 
gions forests, grasslands, vegetation and 
soil, and the marshland reeds resources. 
2 methods and principles 
First we use satellite photos of different 
times and different seasons and aerial mul- 
tispectral photos and conduct different band 
composition coherent covering, stacking, and 
ratio,etc. optical processing. And then, 
combine the processed satellite photos, the 
multispectral photos with the full colored, 
black and white aerial photos to set up the 
interpretation symbols and the indexing ca 
talogue. Finally, we explain the type and 
distribution of various natural resources 
visually, and draw specialized diagrams. 
All remote sensing images are pictures of 
ground objects reduced to certain proportion. 
The characteristics of the pictures reflec 
ted on the remote sensing images are formed 
mainly by the difference in information of 
the tone and form characteristics. 
The information of the characteristic of 
tone is the characteristic of quality and 
the energy of the electromagnetic spectrum 
of the ground objects reflecting on the re 
mote sensing images. Generally, the diffe 
rence in the energy of the electromagnetic 
waves recorded on the same remote images is 
mainly determied by the reflection rate of 
the spectrum of the ground objects. The theo 
retical formula:is . 
W =C K (x) • £ (x A, <?2 ,h >N H" 1 7' ,<iK 
K: the constant of changes with the wave 
length. 
£: the penetrating rate of the ground objec 
ts reflecting and radiating in the atmosphere 
N: the radiating illuminance of the direct 
sunlight and the skylight. 
P : the spectro-reflecting rate of the ground 
obj ects. 
However, on the same remote sensing image, 
K, Z, N can be used as a constant. Thus, the 
above-mentioned theoretical formula can be 
simplified as follows: 
W= K 
A.: the wavelength 
Or. the angle of elevation between the ground 
objects and the sensor 
ft: the aspect angle 
cj>: the angle of elevation of the sensor 
<j> t : the azimuth 
Also: D= K log ^ i is the positive) 
D= K log-^— (j_ s th e negative) 
D: the tone or density or the remote sensing 
images 
As in the same remote sensing image the 
difference in image tone of the adjacent two 
objects A and B are mainly determined by the 
difference of the energy of the electromag 
netic wave, that is by the difference in 
reflecting rate between them: 
iD - K w ^ los-£- 
w a , wh are the energy of the electromagnetic 
waves of A and B objects 
Pa, y Pt are the reflecting rates of A and B 
obj ects 
K w 2 a constant, which influences the other 
factors of the energy of the electromagne 
tic waves 
ip: a constant, which influences the other 
factors of the reflecting rate 
Therefore, according to the known density 
of the images and the reflecting rate of the 
spectrum on various ground objects, we can 
classify various ground objects from the 
remote sensing images. 
The information of the form characteris 
tics is in essence the spectrum of the ground 
o bjects reflecting the rules of the time 
and space of the ground objects, that is due 
to the difference in the composition of ob 
jects and undulation of the Earth's surface, 
the characteristics of the images are for 
med by the difference of electromagnetic 
energy reflecting the same band. The existan- 
ce and attributes of many objects can be de 
termined according to the form of their ima 
ges. 
As mentioned above, the information of the 
form and tone characteristics and the chara 
cteristics of the images as reflected by 
their combination on the remote sensing ima 
ges, which are the main foundations for es 
tablishing the explanatory sybols and in 
terpretation.