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Ecological Sustainability and Urban Green Space |
RINGKØBING
PAPERS |
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Urban Density
and Green Structure Case Studies Ringkøbing
-DK Stocksbridge
-UK Social
Impacts of sustainable Housing Helsinki -
Espoo -SU Political
Instruments Norway
- N Ringkøbing
Area Resources |
RINGKØBING CASE STUDY - AREA RESOURCES COLLECTING DATA
Collecting data on area resources In Denmark collection of detailed information about area resources turned out to be more complicated than anticipated. Data on green space and unbuilt land from existing residential areas This research has involved the collection of data about the actual area use in - mainly - residential areas. These have been the focus of attention due to the general quality of the biodegradable waste and the storm water and because it is possible to address issues relating to local participation and responsibility. Køge - a Pilot Study The provincial town Køge, which has about 40,000 inhabitants, was used for an initial study of actual urban area resources. A number of residential developments in a suburban district and in the centre of Køge were investigated to supplement available statistical information. These results are used representatively, although the number is not statistically significant. So far there is no other information to build on. Plot ratios to control density of development Area use (landuse) is handled in Danish municipal planning by limiting the exploitation of properties within the single planning unit, here termed structure zone. Typically the regulations are based on maximum plot ratios and building height. Plot ratio within single family structure zones in Ringkoeping is typically 25% with buildings one and a half storeys in height. In the town centre the plot ratio is normally 40% - 50% and the height two and a half storeys, although in one part of the central area the ratio exceeds 200%, a figure which would be quite usual in the city of Copenhagen. For the industrial areas it is often stated that a minimum of 25% of the total area must be left unbuilt. These regulations make it possible initially to implement planning decisions about the urban structure and density and later to prevent any unwanted densification. However, this information is not often directly usable for the purpose of this study of the link between urban density and greenstructure: the numbers describe a maximum or minimum, not the actual use of the land, and the gross built area often does not directly relate to the actual area occupied by the buildings, because of a variation in building heights. Other available statistics on built up areas- property size The only other existing data available is information about property size and the area occupied by built structures within a single property, collected by Statistics Denmark from all Danish municipalities. This information has the advantage that it is possible to seek additional information on owners/residents and the number of dwellings, which is useful in calculating the production of household waste, and in the assessment of owner/residents' ability and motivation to take responsibility for the local environment, etc. Statistics on non-built up areas We found that information about the non-built area calculated from the total and build over areas was the best possible source of data to work from in the Køge study. However, there were many complications. Firstly, there is rarely only one registered property per development, more often several, which means that it is necessary to calculate the acual area built on per development. This requires a very good map, which is still not available in many municipalities. GIS maps are very suitable, but implementation of GIS is only just beginning in many municipalities. Secondly, the information available on non built land is often full of errors due to the presence of sheds and other small and more temporary structures, the building/demolishing of which does not require municipal approval (up to a maximum of 10 sq.m). Finally, information on the built area (additions of newly built areas, conversion of areas etc.) is often not updated - the database does not always contain information about new additions and conversions. Such problems have complicated our collection of data. In particular, combining field data and area measurements from plan material with the statistical data to identify inconsistencies have been time consuming. Developing a GIS to record Køge's area resources During this study of Køge's area resources, it became possible to use a Geographic Information System (GIS). In this way we were able to check the consistency between the statistical data and the electronically measured data of built and non-built areas. Despite resolving many of the inconsistencies, many still remain. They have not yet been statistically analysed, but the accuracy seems to be such that it is reasonable to calculate reliable area information from GIS maps, instead of paying for statistical information which would be no more accurate. One problem in using the GIS maps for area calculations relates to the maps having been produced from a base of aerial photographs and consequently not having "closed polygons" available from the start. The analysis could not, therefore, be fully automated to calculate the areas of land involved. Using the GIS software provided by MAP INFO, closed polygones were drawn based on the municipal structure zone maps. This allowed the identification of each structural zone within the GIS and a database was developed to provide information both on the extent and on the characteristics of each zone.
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