1 Introduction
Urban lighting planning is a subsystem of urban master planning and belongs to one of the urban special planning. Urban lighting planning is the principle guiding and comprehensive deployment of urban lighting layout, construction and management in a certain period of time [1]. After surveying the current situation of urban lighting planning in China, it was found that although the overall planning of urban (nightscape, landscape) lighting was compiled, the level of landscaping and lighting of urban nightscapes was improved to some extent, but the implementation and implementation of the planning were still insufficient. For this reason, urban lighting planning, as a newly established special plan, lacks research and support for the theory of its implementation control, resulting in a confusing definition of night lighting planning, making the scope and intensity of landscape lighting implementation unable to meet the expected requirements. It is difficult to carry out scientific and unified management of project implementation.
In the research of this paper, the control lines (such as red line, green line, blue line, etc.) required in the urban planning theory system will be specifically combined to carry out specific research on the urban lighting planning control line.
2 Control line theory in urban planning system
In order to control and standardize various types of urban construction land in urban planning, a “five-line†system has been formulated [1]. As shown in Table 1, the concept of “five-line†is analyzed and compared in urban planning.
Table 1. Comparison of the concepts of “five-line†in urban planning
The analysis of the definition of “five-line†of urban planning includes two layers: one is the description of the nature of land use, and clearly describes the content categories that need to be controlled and protected; the second is to emphasize the control boundary, and the other should cover the type of land that may be involved. Other elements.
3 Urban landscape lighting control line research
3.1 meaning
Drawing on the above-mentioned urban planning control line theory, the urban lighting planning control line is proposed for the urban landscape lighting planning, and is the control of the urban landscape lighting construction scope. In addition to defining the lighting planning land, the urban lighting planning control line should also include control of the lighting object. Referring to the name characteristics of the control lines such as red lines and blue lines in urban planning, the urban lighting planning control line is defined as “bright line†in this study.
In summary, the urban lighting planning control line - "bright line" refers to the control line that defines the urban landscape lighting range in urban lighting planning, including the control of the boundary line of the landscape lighting land and the scope of the lighting object. Among them, landscape lighting objects include lighting for specific functional areas, buildings (structures), squares, roads and bridges, garden green spaces, historical sites, water features, commercial blocks, advertising signs and other public facilities.
3.2 Characteristics
3.2.1 Subjectivity
Urban landscape refers to the landscape or scene of the urban regional space. It is the visual total composed of various visual things and visual time within the city. The existence of the urban landscape will change due to the different subjective feelings of the human being. The object of urban landscape lighting is mainly urban landscape. Different from other types of special planning, the purpose of landscape lighting is to brighten and beautify the city, so that people have a better perception of the city night scene. The “bright line†is the control of the range of landscape lighting objects in a certain area. When determining the range, it is necessary to consider the different landscape components resulting from different perceived people. Therefore, the delineation of "bright lines" needs to fully consider the subjectivity of people.
3.2.2 Spatiality
The concept of “five-line†of urban planning is analyzed, and the control lines are defined for the scope of different types of land use. The control range of the “bright line†is mainly limited to the control of the scope of the landscape object. The urban landscape exists in the three-dimensional space of the city. Due to the subjective perception of human beings, the urban landscape observed by people in the planned area will exist beyond the boundary of the land, and it will directly represent the urban interface that can be observed in the area. When planning landscape lighting, the city interface will become an important bottom view of the planned night landscape and become an integral part of all night landscapes in the area. Therefore, the control range of the “bright line†exceeds the plot boundary of the planning area, including all the landscape objects that can be observed in the area, and is spatial. (Figure 1)
Figure 1. Spatial representation of "bright lines"
4 Influencing factors and delineation methods for bright line delineation
As mentioned above, the lighting planning control line is subjective and spatial, and the specific timing must fully consider the existence of its influencing factors and determine the scientific delineation method.
4.1 Influencing factors
4.1.1 Subjective factors
The lighting planning control line is expressed as the regulation of the urban night landscape. The embodiment of the landscape has strong subjective factors. The physiological characteristics of the human body, including the visual field of the human eye and the visual acuity, will affect the range of the perceived landscape. Some basic psychological needs of people in the space environment, such as openness, closedness, recognizability, etc., as well as different behavior patterns of people in the city, will have an important impact on the perception of urban landscape. The subjective influence of the researcher plays an important role in analyzing the composition of the urban space night scene and is an important consideration for delineating the urban lighting planning control line.
4.1.2 Urban space factors
Urban spatial material form forms urban landscape, and different urban spatial forms constitute different urban landscape images, which directly affect the determination of landscape lighting range. In cities, the types of spatial forms are mainly classified into the following four types: street linear space, square, green space open space, and waterfront urban space. (as shown in picture 2)
Figure 2. Different types of urban space