改革开放以来,伴随着经济多层次的开发和城市全方位开放,我国东南部沿海地区城市(镇)的规模不断扩大,数量不断增加,出现了沿海经济开放区和城市(镇)连绵区。形成了以特大城市、大城市为核心的城市聚集区和经济发展长廊,其地域空间分别位于辽宁中南部、京津唐、长江三角洲和珠江三角洲地区。目前已基本形成特大城市——大城市——中等城市——小城市——建制镇较为合理的城镇等级结构。这些城市聚集区发展的特点是:有两个以上特大城市作为区域的发展中心,辐射和服务功能较强;有直接与世界各国联系的对外口岸;发展中心和对外口岸之间有一条或几条方便的交通干线作为发展走廊;交通走廊沿线及其两侧有众多 Since the reform and opening up, with the development of multi-level economy and the all-round openness of the city, the scale of cities (towns) along the southeast coast of China has continued to expand, and the number has continued to increase, with the emergence of coastal economic open areas and continuous areas of cities (towns). The urban agglomerations and economic development promenades with mega cities and large cities as the core have been formed. The geographical space is located in the central and southern parts of Liaoning, Beijing-Tianjin-Tangshan, the Yangtze River Delta and the Pearl River Delta. At present, basically large-scale cities--big cities--medium cities--small cities--are more reasonable in the township hierarchy. The characteristics of the development of these urban agglomerations are as follows: There are two or more megacities as regional development centers, with strong radiation and service functions; there are foreign ports that directly contact the countries of the world; there are one or more ports between development centers and external ports. Convenient traffic trunks serve as development corridors; numerous traffic corridors and their sides