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The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B7. Beijing 2008
Figure 2. Result of the research’s classification in 2001
4 MONITORING THE CHANGES OF
DESERTIFICATION BASED ON GIS
In support of GIS, achieved the overlay of type distribution,
which was from two different temporal phases of desertification.
Then we discovered the changes of desertification.
Desertification types of changes could be divided into
development, and stability, reversal three basic types. In order
to reflect a certain period land desertification types of mutual
conversion pattern more accurately. The development was
divided into two basic types: significant development and
general development. The reversal was divided into two basic
types: significant reversal and general reversal.
Firstly, in the support of ARCGIS, Do Data coding to the
types of desertification. Respectively, used 1,2,3,4 to
representative severe desertification, middle land desertification,
mild land desertification, no land desertification.
Secondly, in the support of overlay function of ARCGIS
software, overlayed two different types of desertification
distribution map. Then did subtraction operation. First, it is
dentified as significant development areas, that no
desertification translated into land desertification. It is identified
as significant reversal areas, that desertification translated into
no desertification. Then, according the code margin, determined
the change types of desertification, which were generated after
the overlay (Table 3).
At last, automatically generated map of changes types of land
desertification in the study area.
Then, do area statistics of land desertification in different
periods types of changes(Table 4).
From 1995 to 2001, the study area was the development of land
desertification state, development area covered 478.10 km2,
reversed area covered 426.90 km2. The development area was
51.20 larger than reversed area.
5 CONCLUSION
The Article chose two different temporal phases remote sensing
images in typical area as data sources to do the research. By
choosing the appropriate NDVI and index system of land
desertification in the study area, acquired the land
desertification information. Then, in the support of the ARCGIS
discussed convert pattern of land desertification in research area
from 1995 to 2001.Use RS and GIS to do the research on
Monitoring the Changes of Desertification in Typical Area is
advanced, but not yet a very mature, we also need in-depth
research, their applications will become more and more widely.
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[3] Desertification disaster evaluation of remote sensing
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code margin
^-2
-1
0
1
^2
changes type of
desertification
significant
development
general development
stability
general
reversal
significant
reversal
Table 3. relationship between code margin and changes type of desertification
changes type
desertification area from 1995 to 2001 /km 2
proportion of the total area
significant development
114.81
3. 69%
general development
363. 29
11. 69%
stability
2202.35
70. 88%
general reversal
334. 27
10.76%
significant reversal
92. 63
2. 98%
Table 4. Analyse the Results of changes pattern of desertification