Page:John Nolen--New ideals in the planning of cities.djvu/46

NEW IDEALS IN THE PLANNING OF

The classification of cities according to the type or character of the city plan may be considered under three heads: (i) types distinguished by the style of the plan; (2) types distinguished by dominant function; (3) types distinguished by size.

Most cities can trace their origin to military, trading, or commercial requirements. In the foundation of Greek cities, for example, four distinct periods have been noted. In the first of these the city was planned as a place of refuge against hostile attack. In the second, its chief use was in the development of trade. In the third, artistic embellishment was the leading feature. And the fourth period embraces the time of the decline.

Cities generally owe their existence to geography, and such individuality as they have is due largely to topography. The chief topographical characteristics determining cities are the sea, rivers, hills and plains. It has taken decades of urban development and of mistakes to impress upon the cities of the United States the necessity of respecting and conserving these natural features, to which they owe not only their form, but often their very life.

Cities that have been laid out upon preconceived plans may be broadly divided into two classes: the first is the radial system, or what is often called the spider's web plan; the second, the rectangular or gridiron plan.

The radial type has been most common in Europe. The rectangular or checkerboard type has been used widely in the