ERIK LOUW
Research Institute for Housing, Urban and Mobility studies
Delft University of Technology

When we think about densities it is mostly in rather pragmatic way. As a diagnostic tool it is a seemingly objective measure for the ratio of people, activities or buildings to area and is often related to particular planning objectives. In the debate about densities, industrial land use has always been a minor issue. Only in the debates about agglomeration economies, employment density have been studied to some extend.

In general economic geographers and regional scientists hardly analyse densities. Only in land economics employment densities are used as a tool to describe or analyse land performance. In this paper I will discuss the concept of spatial productivity as a way to measure the density of economic activity. Spatial productivity is defined as the amount of added value produced per hectare industrial or urban land and is calculated for the urban regions in the Netherlands.

The papers will discuss the various dimensions of spatial productivity and its relation to densities. It will be argued that spatial productivity is a more suitable way to measure ‘spatial economic’ densities in modern highly urbanised economies than the traditionally used employment densities This is because it relates densities with performance and gives some, but not all, indications of how efficient land is used. Although it may seem that spatial productivity comprehend the complexity of economic spatial relations, the paper will also show how it can, and is, used in spatial planning on a very local level.