The ENVIBASE-Project

Documentation / Online Handbook

Land use and Biotopes

Description of the Problem

Knowledge of the current situation of land use forms the basis for planning. Due to the major changes that have been happening in Berlin since the Wall came down in 1989, the need for such knowledge has become even more important.

Social, political, and economic changes generate new tasks and assignments for a city, many of which cannot be satisfied within the framework of existing urban structures. For the Berlin metropolitan area and its surroundings, a major growth impetus is predicted during the next twenty years as a result of Berlin being reestablished as the capital of a united Germany. At the same time, Berliners are making increasing demands on green and open spaces for rest and recreation, relaxation and play. The multifaceted and contradictory demands upon the urban spaces in Berlin will necessarily lead to changes in the existing land use pattern. Urban planning faces the task of balancing the demands for space against each other and of ensuring a satisfactory compromise between interests.

In order to make effective use of the mentioned plans and applications, it is very important to know the current land-use situation in detail, the changes in land use, and population density statistics.

Data Sources

To collect land-use data, we decided to use mainly colour-infrared aerial photos combined with a multitude of other existing maps and databases. Important maps were used such as the Topographical City Map and the Map of Building Ages as well as the land use inventory maps of the boroughs. The population density was calculated from the number of inhabitants database from the statistical agency, updated each year. The assessment of the availability of public, near-residential green spaces is based on the above-mentioned land use database and the number of inhabitants, as well as on more detailed information about the green and open spaces and the traffic noise map. For the open space development, old street maps and the city master plan were used.

Methods

All information about actual land utilisation is, with one exception, managed and processed by the Environmental Information System (UIS). This enables graphic data-processing of the factual data on the basis of a uniform spatial reference system.

The spatial reference system is provided by a digital topographical basic map in a scale 1:50 000 — the UIS work map. It shows each individual statistical block, which is, as a rule, delimited by streets, with its block number. The numbering and delimitation of the blocks are performed by the State Statistical Office. Block segments comprise the smallest system unit. These delimit different land uses within a statistical block. Altogether there are about 25,000 reference areas. The uniform frame of reference makes clear spatial identification of all factual data possible. A common key which contains, among other things, borough, block, and block segment numbers, is used to assign these data within the spatial reference system.

The current system of land use describes the built-up and the green parts of the city. The categories relate in level and structure to the land-use plan. They describe, for example, residential or industrial areas and, on the green side, parks and forests. The resolution is accurate down to one hectare area. The categories are divided between built-up and green areas. Of course, one area may be recorded in both categories. This is important for some evaluations with ecological aspects. For example, most of the parks in Berlin are also public facilities. These specific areas will get the designation "Public facility" for the built-up use and "Park" for the green inventory. This classification is therefore a mixture between planning categories and actual land use, which you can see, and a map of the actual structure, or from an aerial photo. Some things were difficult to map: for example the difference between residential areas and mixed areas. Mixed areas are defined as areas with a high percentage of residential use and a lower share of small business use. This is not obvious in the shape of the buildings. They require a high level of magnification to be accurately classified.

For the demands of ecological assessment, this classification was not enough. The system was therefore extended to cover the types of urban structure for predominantly residential use. These were further broken down according to their typical construction and open-space structure and their dates of construction. In addition, each type is described by its sealing percentage, percentage of built-up surface area, and its distribution of differently permeable surface covers. All these data are vary greatly through the diverse urban environment. This becomes apparent in the outline when comparing a late 19th-century block with a twenties and thirties block edge or a post-war high-rise construction.

The population density was calculated from the number of inhabitants and the area size related to the block. It could not be related to the block segment because of the data base of the number of inhabitants. So the number of data sets is only 14,000. While developing this work, we could quantify the relationship between the population density and the urban structure types. We can now describe an average population density for each type of urban structure.

The availability of public, near-residential open space is based on several factors and an assessment according to existing minimum values for the provision with public green spaces. The first step was an assessment of which green spaces should be taken into consideration related to their suitability for recreation according to the criteria: area size, area shape, accessibility, and ecological damage. Next was the survey of intake areas. The number of inhabitants of the intake areas was calculated with the size of the green space for the average available green space per inhabitant. The degree of availability was assessed in four classes according to the standard value valid in Berlin from provided areas (more than 6 m²/inh.) to unprovided (less than 0.1 m²/ inh.).

The open space development describes the losses and gains of open space in specific time periods. In other words, the space that was built up in a particular time period. The time periods were set from 1950-1970, 1970-1980, 1980-1990. Additionally, an outlook on potential losses and gains due to the realisation of the current city master plan has been done. This was done by overlaying street maps 1950, 1970, and 1980, the current land use map (from 1990), and the city masterplan from 1994. In cases of problems, data were verified by aerial photos. This map was worked out only analogically.

Creating the land use data base was hard work. About 1,000 aerial photos had to be analysed to classify the 25,000 areas of the spatial reference system. Several different people have been engaged in constructing the data base. Two essential problems arose from this method of work: 1) Everyone concerned limits the categories differently. Even if you give a very precise definition of the types, it seems to be impossible to ensure that all persons concerned understand the definition in the same way. 2) Mapping thousands of areas by hand leads to a high human error potential. This in turn, means there is the necessity for large scale correction.

Altogether it took about three years until a consistent version was in operation. That is too much time given the current speed of urban development in Berlin. Data should be up to date and available by the time it is actually needed.

So the idea was to accelerate and standardise this work using satellite data. There was an investigation of the feasibility of using Landsat TM pictures for this need in 1994. It was determined that the Landsat TM data was not detailed enough to enable an adequate differentiation among urban structure types.

We are going to adopt ATKIS, the Authoritative Topographic-Cartographical Information System that has just been developed by state surveyors using a nation-wide classification system. It is to be updated periodically. This will replace the spatial reference system as well as our land use data described above. Adopting a new system will again bring its own difficulties. Then we hope to concentrate on working out the urban structure types. In this field we already revised the categories. It is not yet clear how we will collect the data. Maybe the current ATLAS Project run by the Centre of Earth Observation from the European Union will deliver new results about using high resolution satellite data in this field.

Results

The results were published in six maps in the Environmental Atlas and are also available on the internet. Also, the original data can be purchased. The maps are:

• Uses of Built-up Areas;
• Inventory of Green and Open Spaces;
• Urban Structure (These three maps are derived from the land use data base);
• Population Density;
• Availability of Public, Near-residential Green Spaces;
• Open Space Development.

These maps give an overview of the real land use in Berlin as a description in most cases, but also as an assessment concerning the availability of public green spaces. It is possible to discern at a glance the main residential or industrial areas, as well as the location of forests, fields, or parks in the city area. You see the dense, sparsely populated and built-up areas and the relationship between green and built-up areas. It becomes obvious that Berlin has a polycentric structure because the Berlin of today has its origin in the uniting of several smaller communities. The development of the green and open spaces shows the permanent increase of the city since World War II. While the main parts of the reconstruction of West Berlin took place soon after the war and until 1970, the development of the new quarters in East Berlin was done only in the 70s and 80s.

Uses

The knowledge of the land use in the spatial and classified detail forms an essential basis for all urban development and landscape-planning standards, both at the local and at higher levels. However, this knowledge also permits information to be derived for the requirements of the Environmental Information System regarding the formation of biotopes and vegetation structures, climate relationships, condition of the soil, the degree of soil impermeability, the new formation of groundwater, and a carbon dioxide cataster.