2.1.1 50m mesh DEM 
GSI have been producing digital elevation model(DEM) in 
the whole country. These are about 250m grid interval (mesh) 
DEM and about 50m grid interval (mesh) DEM. We used 
this 50m grid interval DEM to make terrain model. 
2.1.2 Road data(main road) 
GSI also produces digital road data. However, only main 
road data administrated by the national government and so on 
are available at the moment. 
2.1.3 Houses and buildings 
GSI does not produce digital cartographic data of houses and 
buildings corresponding to medium scale maps. They have to 
be collected with a digitizer from medium scale topographic 
maps manually. 
2.1.4 Vegetation boundary 
Vegetation boundary is the most important data to express 
realistic landscape images. However, GSI have not produced 
vegetation boundary digital data of medium scale maps. We 
have to get digital data by using the same method as houses 
and buildings data collection. 
2.1.5 Water boundary 
Water boundary is also collected by digitizing with a digitizer 
from 1:25,000 scale topographic map. 
2.1.6 Large scale data from Digital Mapping data 
Large scale houses, road boundary and water boundary etc. 
From digital mapping data are used for expression of large 
scale scenery. 
2.2 Creation of three dimensional space model 
After preparing digital cartographic data, three dimensional 
space model are generated by using DEM. This process is 
carried out automatically with batch program. This three 
dimensional model can be converted to DXF, so if we would 
like to edit details of the model, we can use CAD system for 
It. 
2.3 Visualization of three dimensional space by using 
Computer Graphics method 
After creating three dimensional model, we have to paint 
color to each polygon structuring three dimensional model. 
Each polygon has identity number according to its category, 
and each polygon can get identical color by using computer 
graphics method and technology. First of all, the surface 
model are created from three dimensional space model. 
Shadow and lighting are calculated to make surface model. 
After this, to make more realistic view, texture is mapped 
onto surface of 3-D model. Texture can be created from 
scanned photographs. Behind landscape, we can put an image 
of clouds made from a photo. We can also use bump map 
method to express surface of model. Bump mapping is 
364 
effective to express rough surface. We can also express a 
variety of landscape images by changing the textures. For 
example, if we use a picture of snowing, scenery of winter 
can be expressed. 
3. EXPRESSION WITH DATA OF LARGE SCALE 
MAP 
In this study we had been using digital cartographic data 
collected from 1:25,000 scale topographic map mainly. But 
this scale data can hardly express small objects such as 
houses, buildings and so on. So, we have tried to use digital 
mapping data on a scale of 1:2,500 in order to express small 
objects such as houses and buildings individually. Digital 
mapping data of houses and buildings have X Y coordinates 
in two dimensional space, but Z coordinates are not prepared 
in digital mapping data. We need height information of 
houses and buildings to express three dimensional space 
from the digital mapping data. Therefore, we put height 
information of houses and buildings onto digital mapping 
data to create three dimensional model. Roof shape attributes 
were also created to express house details. Three kind of 
roof shape namely flat roof, kirizuma roof (triangle cylinder 
shape) and Yosemune roof (pyramid style shape) are 
modeled for more realistic expression of houses and 
buildings. 
We also try to express some kinds of three dimensional space 
about built-up area or urban area with large scale digital 
cartographic data for the purpose of expression of the details. 
Fuji city in Shizuoka prefecture which is located in middle of 
Japan was selected as a test areas. The population of Fuji city 
is about 240,000. The center of the city is built up with many 
old house made of wood and some buildings which height 
are less than 10 stories. Fuji city has created digital mapping 
data for whole area of the city on a scale of 1:2,500. We used 
the digital mapping data for our study. We selected center 
area of the city including the city hall as a test area(Figure 1). 
Digital data structure of road of digital mapping data are 
different from 1:25,000 scale cartographic data. Data of 
block area are collected in this large scale digital data, that is 
to say boundary between road and block are dizitized. 
Owing to this data structure, it is possible to create every 
kind of street as compared with 1:25,000 scale digital 
topographic map. 
These methods bring a little effect for expression of details. 
But it is not enough to express details. Some special items, 
for instance, tree in backyard or park, advertisement board, 
telegraph pole etc are very important for the expression of 
urban area. Usually, these special items are not prepared in 
general digital cartographic data. We found results of our 
study dose not express a built-up area of ordinary Japanese 
city. 
4. EXPRESSION OF GEOGRAPHICAL FEATURES 
FOR STEEP SLOPE 
It is difficult to express cliffs and river banks in middle scale 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. Vienna 1996 
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