A GIS-based implemental framework for landscape design - IEEE Xplore

A GIs-Based Implemental Framework for Landscape Design * Liu Yong, Xu Congfu, Chen Weidong, Pan Yunhe (State Key Laboratory of CAD&CG, Zhejiang University, Hang Zhou, 310027) (Institute of Artificial Intelligence, Zhejiaug University, Hang Zhou, 3 10027) Abstract - Better information leads to better design. In landscape design, the designers care f o r what the plans will affect the urban more than what their plans will look like. In this paper, we discuss some key techniques in a GIs based landscape design system. With the advantage of the GIs, designers can make better decisions. A protorype named landscape evaluation system (LES) has been implemented. In LES system, designers can build up their virtual evaluation world, and establish the interrelationship ofthe entities in their virtual world. Keywords: Design, GIs, Relation Define, Evaluation

1 Introduction In landscape design, computers are introduced to indepth application. For decades, urban planning was done by drawing plans and building elaborate models from wood and pasteboard, and the computer technology implementing in the landscape design greatly revolutionized the planning process [ 5 ] . However, the majority of the current software just plays the role of recording data and helping designers express their ideas. As to the decision making process they are helpless to designen, mainly because of the following reasons:

designer couldn’t oversee the planning results of their design cases although they can plan the cities (regions) carefully in advance [6]. While each designer has different options in the same case, they should use an interactive system to help their design. In this system, designers could define their scales and objects (including objects attributes, hierarchy of objects) in their mind, the rules and interrelationships between the objects. And then they should only dispose the objects that they predefined beforehand. The project evaluation system (we call it landscape evaluation system, LES) would tell designers what their design will affect the whole urban region in these key fields such as economy, ecology, traffic, vision quality etc. Figure 1 show the difference between the traditional design pattern and the new design pattern using LES. Designel

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a) Traditir Traditional Landscape Designed Pallems Base on AutoCAD, 3 Mxh

Visual effect Firstly, most landscape design systems are inflexible and limited to present explosively increasing settings in the area. Therefore due to the weak assistance to designing, such systems easily get out of date. Secondly, most landscape design systems are static that cannot represent the interrelationships of settings and the effects of time on landscapes. That’s why designers rarely rely on these systems that are lack of practical values. Finally, the evaluation ability of these systems is limited to presenting current situation but they can’t predict future development. Today, landscape design not only means landscape quality of the cities (regions) hut alx, includes traffic, economy, ecology, history protected etc. Current design software focuses on the real landscape simulation more than the management of geographic objects; secondly, current graphics software only builds static scene. This software can’t offer dynamic information of the landscape to predict what will happen. In fact, the most awkward thing of the traditional landscaping design methods is that * 0-7803-7952-7/03/S17.00 0 2003

IEEE.

Figure 1 Difference of Two Design Patterns In following parts of this article, we will introduce the landscape evaluation system and its implementation in the case of Hang Zhou Westlake.

2 Related Work Shiffer [7] first introduced multimedia into the landscape planning in 1995. Stephen M Ervin [SI has found the shortcoming of the traditional design pattern, introduced a new method, which integrated advantages of both GIS and CAD systems. Nowadays, the urban planning assistant systems have focused on the virtual digital city rebuilding from GIS data [2,3,4,7]. The virtual

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reality will greatly enhance the design, but they can’t tell designers how the design will affect the urban, and they can’t offer a dynamic forecast of the design. Above all these systems have more concerned about what the urban looks like in the designer’s design than answering the questions which fields will be affected by implementing the designers’ proposes. So we present a threedimensional dynamic GIS model for landscape planning [I]. Designers would need a more powerful tool which could provide a freely environment to present their ideas and evaluate their design case before their planning.

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shape when generating instances. Tendency has been used to describe the entities’ evolution states. For example, there might be two trees that have all the same attributes but the tendency, one may be a growing tree and the other may be a dying one, so we can distinguish them by tendency attribute. We also need a time-scale attribute to describe the dynamic process of the entities, so timestamp will be introduced.

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Components of LES

The LES system is composed of three sub-systems, including entity design sub-system, interrelationship design sub-system and evaluation sub-system.

3.1

Entity Design

There are various theories ahout the landscape planning, and every designer tends to use his own theory in practice. Usually the landscape virtual world is in the multiple-form. Therefore the traditional standard entity hierarchy cannot meet the requirements for multiple design theories. For the purpose of supporting the designers to express their own options to their projects, OOGIS technology has been widely used, but these current OOGIS systems [9,10] all have fixed object hierarchies. In the entity design system, the entity hierarchies could be multiple forms by which the designers can freely define their basic objects and object’s inherited relations. The attributes also could be added to each object (entity). The entities are composed of two kinds of geographic objects in LES. One kind of these objects are the basic abstract geo-objects that are predefined by the entity design system, and, there are also some userdefined geo-objects that the designers could build by extending their own objects from basic abstract geoobjects. Abstract geo-objects will never be generated by the instances, because these basic objects are only concepts. Figure 2 shows the prefab basic objects defined in the entity design system. User-defined geo-objects are defined by extension from those basic objects; they could be generated in the following evaluation system. Because the virtual world constructed by entity design sub-system is extensible, the attributes of basic entities can be inherited. The attributes of geo-base objects have bean divided into two categories, one are attributes preserved by the system, the other concerns the common attributes such as shape, tendency, timestamp etc. In LES, shape has become an object’s property that could be initialized in the entity design process, then, the user-defined entities would display by the pre-setting

Figure 2 Object Hierarchies (Only abstract entities)

3.2

Interrelationship Design

The most significant difference between LES and other object oriented landscape design assistant tools is that LES provides a powerful relation design tool to describe the reaction among the entities. Those OOGIS 19,101 systems that focus on the object hierarchies are static states of the concept. By adding this relation system above, our system can build a dynamic virtual concept world. In landscape design, designers pay more attention to what their planning will change than what their planning will look like, so a dynamic system might be more helpful to them.

3.2.1

Format of Relation A relation in design system consists of five parts: subject, object, condition, distance and result. Subject is the entity that will be influenced by the objective entity. Object is the entity that will influence the subjective entity. Condition means that the action of current relation will be mggered if this condition meets. Result defines the correspondence action, which will be applied when condition has been contented. During the design process, the designers may only care a certain scale of his design case, so a distance parameter should be added to the relation. When adding the parameter of distance, the distance means the effective area of this current relation. For example, a relation defined in tbe table I . here the house is the subject entity, the park is the object entity, and this relation means that if House’s level < 5 is true, and distance less equal 400 meters, then house entity’s athibute landscape-quality’ s value minus 1.

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3.2.2

Operation in Relation The relations are constituted by the combination of those entities’ attributes and operations, so the expressive ability of relations is determined by the operation ability of those attributes. There are two kinds of operations in landscape design, mathematic operations and GIS topological operations. Most of the attributes in LES are numerical values. Therefore mathematic operations become the basic operations in relation design. The basic mathematic operation can also be composite to a complex function. In relation design system, there are also some GIS topological functions provided such as function of getting max distance, getting min distance function, getting distance function, judging disjoin state function, judging overlap state function etc. lation in LES Result

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3.2.3

Temporal Factors in Relation LES is a dynamic evaluation system. In dynamic systems, temporal-factors are the most essentials. There are three main temporal factors in LES. First, the time range is called process of evaluation. The time range starts from the beginning of the evaluation, and ends at the last time state. So the time range equates time state at the end of evaluation minus the time state at the beginning. The evaluation may be various types, so the time range may be multi-levels. That means the time range may be some hours, or some months, or some years, even hundreds of years. Second, the time interval means the time sampling alternation. The time interval is the shortest temporalunits in current evaluation process. When it goes to the next time interval, the evaluation system updates attributes by the new state data. Third, the time ratio, a definition imported from map ratio is defined as the equation 1.

correct sequences. A certain time system could be chosen, and all the other time systems would be converted to the standard time system by the time ratios. For example, when we evaluate the plant ecology system, the time range may be several years, and the time interval may be one year. However, in the evaluation of the atmosphere pollution, the time range may be one year, and time interval may be several days.

In LES, each entity has an attribute, timestamp, extending from their base object. This attribute is used to represent their own time state updated by LES during the evaluation process. LES will keep the timestamp synchronization automatically. The timestamp attribute can also be treated as a parameter in the condition part of a relation. By this way, designers could apply and control their own planning in time scale.

3.3

The evaluation system should inform the designers whether their planning is well or bad supported by the CIS engine. Usually an excellent plan will be a tradeoff combining various orientation factors such as economy, traffic, resident convenience etc, so designers may want to overlook all the evaluation results of these concerned factors. Each designer will have his own option of the evaluation model in the same orientation factor, so the evaluation system must be self-defined. In our evaluation system, a score system is established to feed back the evaluation result. A higher value of score means a better plan quality. By this way, designers can make the plan comparatively both in time scale and orientation factors. As there are innumerable types of evaluation models, the designers could define their own evaluation model in evaluation system. An evaluation model is determined by its’ structure. For example, value of a housing depends on its size, age of structure, design, view, proximity to school, etc. Bigger housing might have higher value than small one if every other condition is the same. Thus, once you determine the attributes of the commodity and collect these data, you can estimate the value of each attribute by doing regression.

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= TcurTm T $ m dnrd Map ratios are spatial concept, and time ratios are temporal concept .The evaluation process has various types, so the time system is multifarious. There must be a standard time system, by which all the time systems can exchange information and communicate each other on

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Evaluation System

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Figure 3 Internal Organizations of the LES

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Approach and Instance

Approach Our implementation is written in the JAVA programming language using MYSQL database. Using java database interface (JDBC) to store the entities' attributes and class hierarchy. GML (Geographic Markup Language) [ I l l is used to describe the shape attribute of entity. Figure3 shows the architecture of this system.

Instance In the project of Hang Zhou West Lake launched by Harvard University Graduate School of Design, we use the plan of a region along Qiantang River, defining the entities such as park, school, uptown etc (figure 4). The evaluation in time scale displays in Figure 5 .

Figure 4 Entities design

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Conclusion

This paper briefly introduces the puzzle of those traditional landscape planning assistant tools. The designers want to know all their concemed factors (traffic, economy, ecology etc.) during their plan process, but traditional tools can't offer the feedback of those concerned factors. We propose a dynamic planning method in landscape design, and implement a prototype of LES. The aim of the LES is to combine the information advantage of CIS to help designers make their decisions, which means better information leads to better design. The LES facilitating and improving the planning process has the following advantages:

e The system has been applied as a highly selfdefinable system. Designers can build their virtual concept world by the entity design system and define the interrelationship between entities and define the evaluation models. That would extend the implement of this system, in practice, there are all kinds of design directions, and every direction has its' own concerned entities and interrelationship. 0 The system offers a timestamp, which is available for the dynamic evaluation, in landscape planning. What the future region will look like affected by this plan may be greatly useful for the designers. 0 The system provides an instant feedback. When designers revise the plan or change the attributes of the entities, there will be a quick evaluation result feedback to them, and the old result will be saved, which will improve the productively of designing. The future work may focus on these following part: establishing an interrelationship and evaluation model database, which increases the reuse ability; with the help of GML [ I l l , the system may be implemented in a distribute environment, distribute designing.

6 ACKNOWLEDGMENTS The Project was supported by Zhejiang Provincial Natural Science Foundation of China (No.602045), and was partly supported by Harvard University Graduate School of Design. Thanks Dr. Jiantong Xia who provided the resource related to the project "Altemative Future for the West Lake, Hang Zhou, China".

References

Figure 5 Evaluation Result in Time Scale for traffic, economic, landscape

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