Type: Project Other Data - June 15, 2021, 11:43 a.m.
Much digital plan data is of such good quality that it makes sense to use it to obtain insights into what is being planned, where, how and when. A typical question is how many building reserves exist. That means, of all the land that is zoned as building land, how much of it has already been built on, and how much is zoned but has not been built on yet, in which case it is a potential location for future construction. Besides plan data, information from building registers is necessary for that calculation. Also, the complexity of such an indicator could range from a simple calculation of plots that have not been built on yet, to a detailed calculation of, e.g., how much floor space (floor-area-ratio) has been designated by the respective plan compared to the floor space that already exists, thereby indicating potential for densification. However, the latter requires very high quality data and unambiguous plan regulations.
To get a simple overview of what we plan, efficiency ratios based on the zoned building land can be used. The enclosed shows data from Austria, Switzerland and Denmark. The table shows that Austria has, compared to Switzerland, a much higher average of square metres building land per person. This can indicate a different planning practice in the countries, but it might be as well caused by differences in the planning system, the digitalisation and the definition of categories (e.g. if transport or summer house areas are included or not). Within countries the context would be similar, still, planning practice and even regulations (as e.g. in Austria) can be different. This is shown by the calculated index (zbl_index). There we can see a familiar pattern, with cities and urban regions as Vienna and Zürich being more dense and therefore below the national average in m2 building land per inhabitant. The numbers of Denmark seem not comparable, probably caused by different planned land use definitions. Anyway, the index shows a similar picture regarding differences between urban and rural areas as in Switzerland and Austria.
More details can be found in the final report of DIGIPLAN, section 4.2.