# Full text: Mapping without the sun

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use/cover type. We calculated the area change ratio for the main
land use type in the five series time periods(Tab.l). It can be
seen from Tab.l that the area of cropland, woodland, and
grassland were reducing continuously, whereas the construction
land, water, and unused land area were increasing obviously.
Change percent of the land for construction was the highest in
the four comparison periods, It had been rising since the first
studied period( 1977-1987) by 7.1%, and arrived at the top of
10.8% in the forth period(2000-2005). The result is caused by
growing population and urbanization. The population is dense
and quickly increasing in Three Gorges Reservoir Area. It had
grown from 14.8 million in 1992 to 20.0 million in 2004 (http: //
www.3g.gov.cn). This growth in population and urbanization
had increased the demand for food, houses, and factories (Hunter
L M, 2004 and Semwal R L, 2005). Furthermore, The Three
Gorges Project accelerated the regional economy, leading to the
rapid rise in the use of construction land.
Land use type
1977-1987
(%)
1987 -1995
(%)
1995 -2000
(%)
2000-2005
(%)
Cropland
-0.107
-0.055
-0.059
-0.295
Woodland
-0.022
-0.082
-0.157
-0.250
Grass land
-0.040
-0.030
-0.129
-0.047
Water land
0.389
0.090
-0.551
9.589
Construction land
7.104
8.118
14.471
10.776
Unused land
0
0
1.312
-7.371
Table 1. the area ratio of land use / cover changes in Three Gorges Reservoir Area
3.2 The Dynamic Degree of Land Type Area Change
The dynamic degree of land type area change indicates the speed
of annual land use area change, which is an important index to
show change. It can describe the speed of LUCC in a certain
region quantificationally. The calculation formula is
D = A ‘ 2 ^ x—*—xl00%
1 ^2 — fi
Where A tl = area of a kind of land use type in time tl
A,2 = area of a kind of land use type in time t2
The results according to this formula are shown in Tab.2
Land use type
1977-1987
(%)
1987-1995
(%)
1995-2000
(%)
2000-2005
(%)
Cropland
-0.011
-0.008
-0.012
-0.059
Woodland
-0.002
-0.012
-0.031
-0.050
Grass land
-0.004
-0.004
-0.026
-0.009
Water land
0.039
0.013
-0.110
1.918
Construction land
0.710
1.160
2.894
2.155
Unused land
0
0
0.262
-1.474
Talbe 2. Dynamic degree of single land use in Three Gorges Reservoir Area
From Tab.2, we can see in the four periods, cropland, forest,
grass all reduced annually in a lower speed, however, the land
for construction increased in a higher speed annually, and the
change was accelerating continuously in every following period.
For each type the most outstanding period is: 2000-2005 for
cropland by 0.059, 2000-2005 for forest by 0.05%, 1995-2000
for grass by 0.026%, 2000-2005 for water by 1.918%, 1995-
2000 for construction by 2.894%, and 2000-2005 for unused
land by 1.474%, which indicates that in third period and forth
period (Three Gorges Project construction time) land use
converted most rapidly. The main reason is the rising water line
of Three Gorges dam.
3.3 land transformation matrix
Land transformation matrix is to show the pattern of changes,
namely, from what to what. We made land transformation matrix
in every time period to track the change. Limited by paper
length , we took an example for 2000-2005 period in which the
amount of land use changes was the greatest. The land
transformation matrix during 2000-2005 was shown in Tab.3.
Jn
From
Crop
Wood
Grass
Urban
Village
Other
built-up
Water
Unused
land
Cropland
0
0
59.99
5.25
5.41
0
0
Woodland
0
0
9.68
9.09
4.87
3.77
0
Grassland
0
0
3.46
4.88
5.72
7.30
0
Urban land
0
0
0
0
0
28.07
0
Village land
0
0
0
0
0
0
0
Other built-up
0.22
0
11.77
0
0
0
0
Water body
0
0
1.53
0
0
1.77
0
Unused land
0
0
0
0
0
0
0
Table 3. Land transformation matrix during 2000-2005
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