The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Voi. XXXVII. Part B4. Beijing 2008 
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the orientation of cliffy slope . 
geographical entities, as indicated Figure 2, 3,4,5. 
1 I T I T T I I Ï I I Ï I T T I 
Figure 2 cliffy slope symbol 
2.2 Map Symbol’s Label 
2.5 Map Symbol’s attribute characteristic 
A non-single map symbols can represent different objects by 
combination, but as a map, it should not only show the real 
world to people, but also be looked wonderful. So it’s necessary 
to rendering means. We usually play up the size, color, line type 
of the symbolic elements, and so on. 
The map symbol can express different geographical entity, and 
symbol is usually the same when the same type of geographical 
objects, as shown in Figure 3. Namely this symbol can show all 
triangle reference point; we can’t differentiate the different 
attribute reference point. If every triangle reference point uses 
different symbol, the symbol system will become very 
complicated, even more detrimental to identify the entities. In 
order to solve the problem, we usually regarded a certain 
attributes of the entity as a symbol and differentiate the same 
type entities that have different attributes. For example, triangle 
point is used to symbolize the reference point and the attribute 
of the objects is added to symbol for differentiate them, as 
shown in Figure 4. 
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Figure 3 triangle point Figure 4 adding attribute to 
differentiate the objects 
2.3 Map Symbol’s Random Characteristic 
2.6 Map Symbol’s scale characteristic 
With the widespread era of the computers, electronic maps 
enrich our vision. As we all known, the position of points ^ 
lines^ regions in an electronic map is its actual location, but the 
symbol has scale characteristic. The position of points^ lines> 
region in the paper map is in proportion to zoom in on the map, 
and the symbols has also size. This is scale characteristic of a 
map symbol. 
2.7 Map Symbol’s multi-expression 
In the same type of geographical entities, in addition to marking 
text, attributes is usually the same symbols to express. That is, a 
map symbol that is the same type of geographical entity. For 
example, all the scarp on the ground are not reinforced to 
express Figure 2. 
2.8 Map Symbol’s law 
Map symbol’s law refers to map symbol elements in the 
distribution, with the present law changes. Such as the laws of 
the changing line are filled with symbols, as shown in Figure 6. 
Map Symbol’s randomicity indicates that the symbol expressing 
the map symbol’s non-orientation character have a certain 
randomness, for instance the symbols’ distributing n sizeN 
orientation etc. As shown in Figure 5, the symbols of a forest 
filled with symbols reflect a certain randomness. 
o 
o o 
o 
o 
q eucalypt 
o 
o 
o 
O 
O 
o 
o 
Figure 5 the symbols of a forest filled with symbols 
2.4 Map Symbol’s Combination Characteristic 
In order to express complex and changing geographical entity, 
the map symbol is a non-single map symbol. Symbol is usually 
a combination of symbols elements (for example: points, lines, 
text, images, triangle, rectangle, circle, arc etc.), a combination 
of different type symbols reflecting the difference between 
Figure 6 the laws of the changing line 
2.9 Other spatial features based on the characteristics of the 
space 
Expect for the spatial orientation characteristics, map symbols 
have other space features, for example, map symbols can reflect 
the geographical entity of length, area, orientation, geographic 
entities, such as spatial relationship between the characteristics 
of space, as shown in Figure 6