中文摘要：

变比例尺可视化技术被广泛应用于城市路网的地图制图，其基本思想是采用较大比例尺突出显示城区的密集道路，较小比例尺显示并不重要但对路网布局起辅助作用的周边道路。目前，不少研究是通过使用坐标转换公式及参数组合对路网进行变换，以得到较理想的变比例尺效果。然而，这类方法常难以避免路网较大的变形和道路要素的空间冲突。鉴此，本文结合顾及道路等级的形变约束规则和基于支持向量机的线相交约束规则，建立了二次规划算法的等级道路网变比例尺模型，动态优化道路网变比例尺的效果。本文以广州市增城区规划建设的“一核三区”道路网作为试验对象，分别与可调“放大镜”式地图投影和Focus＋Glue＋Context模型进行比较。实验结果表明，本模型能得到较为理想的变比例尺效果，且具有良好的自适应性和实用价值，为地图变比例尺可视化研究提供一种可控制地图变形过大和解决空间冲突问题的新方法。

英文摘要：

Variable-scale visualization technique has been widely applied in the representation of road network data. The main focus of this technology is to highlight the dense central area in a limited map layout with largescale display method. On the other hand, the marginal and assistant map contents, which are relatively unimportant, will be displayed in small-scale. However, in previous studies, methods using coordinate transformation formula may cause excessive map deformation and spatial conflict among road elements. To solve these problems, a quadratic programming model is proposed to improve the visual effect of variable-scale transformation. In this paper, a line distortion rule based on road grade is constructed. In addition, a spatial conflict constraint rule based on support vector machine is applied to eliminate topological errors of road network. Finally, the road network data in Zengcheng District of Guangzhou city are used to testify the purposed model and the method in this paper. The result shows that this model can dynamically improve the visual effect of variable- scale. Conclusively, this paper provides a new idea to deformation controlling and spatial conflict elimination in the field of variable- scale visualization research.