DECISION SUPPORT SYSTEM
FOR PLANNING ROUTES CONSIDERING ECONOMIC
AND ENVIRONMENTAL ASSESSMENT USING REMOTE SENSING DATA

Abstract

Recently, it is increasingly important in planning a big infrastructure project to consider not only economical but also safety and environmental problems. For an economical route evaluation, the route which involves minimum amount of earthmoving in boring tunnels or filling up valleys must be found out. But in view of a safe route, the nature of soil and fault under the planned routes should be considered of the geometrical condition of places which are prone to earthquake. Furthermore for the environmental assessment, the planned routes must circumvent historical sites, hospitals and schools. From the landscape point of view, the routes should not spoil the beauty of nature and the atmosphere of cities. In planning a very long route, the assessment of these matters takes much time.

To plan a route considering these complicated conditions, VISPER(a visual and interactive economical route planning system) has been developed based on remote sensing data coupled with the image data and the altitude data, graphical user interface and geometry information processing technology. Routes can be defined through image maps on CRT displaying both contour and selected geographical information. It is very easy to know how the areas has been developed. Because the recent colored image maps of the target areas can be easily recognized, a new geometrical information, such as a new road, are available. As the cross section of a selected route is displayed at the same time, gradients of route can be decided easily.

The system can immediately calculate the total length of sections having the same depth from the surface, and find the total cost by summing up unit cost for each depth. The system can show those image maps of planned route. The geometrical condition of the route can be easily checked on CRT display. If maps of historical sites and hospitals are employed, these obstacles can be eliminated from route environments. The environmental assessment involves the noise problem and the landscape problem. For evaluation of landscape along the planning route, aerial view is effective. By using population mesh data, estimation of the number of people exposed to noise is possible

With this system, we can easily estimate results of each plan by simulation and make up better routes in each criteria.

KEY WORDS

Transportation, Social science, Environmental science, Computer Aided Design (CAD), Civil engineering.

INTRODUCTION

In route planning, as shown in Fig. 1, there are complicated conditions to be considered in addition to alignment and gradient. To make a good plan, it is necessary to consider those parameters sufficiently.
For this purpose, VISPER (Visual Integrated System for Planning Economical Routes) which can handle remote sensing data, many kinds of theme maps and mesh data of social conditions for giving a route planner information or calculated result has been developed.

REMOTE SENSING DATA

Using this system, a higher quality route planning can be done in shorter time. This paper proposes new route planning method by means of VISPER.
In this system, remote sensing data measured by French satellite SPOT is used. The data consists of black-and-white panchromatic information and multispectral information, and its resolutions are 10m and 20m respectively. 20m-mesh data obtained from panchromatic information by parallax is taken as the elevation data. Data color-composed from multispectral information is taken as data of topographical color.

PRINCIPAL FUNCTIONS

Principal functions are the group of commands for drawing routes on the imaginary background model in VISPER.

Topographical image display

Color image of topography by remote sensing is displayed on the computer screen as Fig. 2. It enables us to recognize land use of target area.

Contour display

Contours are quickly displayed by the high speed algorithm

Railway route drawing

Routes can be drawn by I.P.'s (Intersection point), which are vertex of line segment, through image maps on CRT displaying both contour and selected geographical information. The operation is very quick and easy, because lines are specified by pointing each vertex with mouse. The system replaces the connecting part of the two line segments with the curved track that has default radii. In case of need, the route planner can change the radii partially. As the line profile of a selected route is displayed at the same time, gradients of route can be specified easily.(Fig.3)

Railway gradient drawing

Whenever height of some of I.P. is changed, gradients of both front and rear segments are automatically calculated and displayed. So it is easy to specify gradients appropriately(Fig.4)

TOOLS FOR COST

Approximate estimation of construction cost

Estimation of approximate construction cost is very easy. We assume that approximate construction cost is estimated by the style of construction. The system can immediately calculate the total length of sections having the same depth from the surface, and find the total cost by summing up unit cost for each depth. The system can show an image map of planned route colored by depth (Fig. 5). These estimation and display, which takes a few seconds, are effective as compared with estimation and drawing by hand.

TOOLS FOR SAFETY

Theme map display for safety route

In view of a safe route, the nature-of-soil and fault under the planned routes should be considered for area which are prone to earthquake. For this reason, the function to display theme map which is imported by using scanner, is developed. As an example, Fig. 6 shows nature-of-soil map (Imoto 1989) on computer display. Route overlaid on nature-of-soil image is possible.

TOOLS FOR ENVIRONMENTAL ASSESMENT

The interest of environmental assessment is increasing day by day, and there are some environmental problems concerning railway. Several functions concerning noise and landscape were developed.

Aerial view display for environmental assessment

For evaluation of landscape along the planning route, aerial view is effective (Fig. 7). And when the route is forbidden to be seen from tourist attractions, route planner can search for place where the route is seen using the function of identification of area exposed to noise. Because the function searches for the barriers.

Mesh data display for environmental assessment

Social condition such as population may make the noise problem serious. Accordingly referring to social condition is important for considering environment assessment. As social data is supplied in form of mesh data, the function for handling mesh data was developed. We discuss Kyoto area by way of example. Fig. 8 shows the map with a scale of 1 to 100,000 of Kyoto area. Fig. 9 shows population mesh data (Land planning and coordination bureau 1987). The population along the route is obvious. By using population mesh data, estimation of the number of people will be exposed to noise is possible (Fig. 10).

CONCLUSION

For high quality and effective route planning, the system that integrats the social condition with topographical condition, VISPER, was developed. The system is started to put to practical use. Hereafter we wish to develop the algorithm to search for optimal route.

ACKNOWLEDGMENT

We are deeply indebted to Mr. Masaki SATOH and Mr. Yoshimasa TADENUMA (JAPAN RAILWAY CONSTRUCTION PUBLIC CORPORATION) who made suggestions.

BIBLIOGRAPHY

Imoto N., et. al. 1989. "Geological Sheet Map 1:50,000 Kyoto Seihokubu" , Geological Survey of Japan(in Japanese).

Land planning and coordination bureau, national land agency. 1987. "Numerical national land information"(in Japanese) .

Nozue N. and Shirotori T. 1996. "3D Visual Integrated System for Planning Economical Routes Using Geographic Data" RAILWAY TECHNICAL RESEARCH INSTITUTE REPORT, vol.10, No.4, 1996(in Japanese).