I don’t know much about urban planning in Jakarta even though I have live there for many years. So, I won’t say much about that. But, here is what I know about how Swedes planning its urban area ^^
Stockholm, the capital of Sweden, encompasses 14 islands with total area of 188 km², is a home for 2.3 million people. Its inhabitant is keep on increasing and so Stockholm has to keep up with its city development. Even so, the city never forget to always emphasize on its sustainability.
However, due to many aspects to be concerned about, somehow, it is difficult to make an assessment as comprehensive and objective as possible. Some aspects are land use, transportation modes, protected area, and geology type. So, in order to build competence for the sustainable urban planning analysis and assessment, it is essential to build on models representing the concerned aspects. So, how does Stockholm build its models?
As what I learned during my study here, Stockholm genuinely like to use Geographic Information System (GIS) and Idrisi software (at least these 2 software are what I learned here. I believe there are more complicated software they use).
So, here is one of the example of modelling: ecological village model. Ecovillage is a village in which human activities are harmlessly integrated into the natural world in a way that is supportive for healthy human development, and can be successfully continued into the indefinite future (Gillman, 1991). Totally a cool things right? And somehow, Swedes certainly love this things. In this study, we want to look for the best site of ecovillage for 50-100 houses with area of 0.25-0.5 km².
Thus, how do we start develop the model in Idrisi software? Let’s make a simple breakdown.
- Set the criteria
- Determine the factors and constraints
- Gather the raw data input
- Make the model to process the raw data
- Run the Decision Wizard
- Choose the best site locations
- Visualize the final output with GIS
It seems simple like? Haha. But my friend and I spent 20 hours to discuss and run this in the computer. It was quite challenging and I learnt a lot so it was totally worth it. Let’s get through this step one by one.
Set the criteria
Criteria is the aspects that we concerned about. As I said before, some examples are land use, renewable energy potential, and transportation modes. To have too many criteria is not good as our ecovillage’s location will be too strict, and we have less choice. But, to have few criteria is not good too as our ecovillage’s location is not that sustainable as we intended. In our case, we set 10 criteria, among others: (1) public transportation access, (2) protected area, (3) the ideal area of ecovillage, (4) proximity to job and service places, (5) waste management, (6) proximity to waterbody, (7) slope of the area, (8) solar energy potential, (9) independence of food production, and (10) geology of area.
Determine the factors and constraints
We use the criteria as a basis to determine the factors and constraints. What is the difference between both? Factor is a criteria that enhances or detracts from the suitability of a specific alternative for the activity under consideration. Factor has been expressed in the form of continuous scale using reclass which contains value from 0 to 255. The higher the value, the more suitable the location for ecovillage. On the other hand, constraint is a factor that limit the alternatives under consideration. Constraint has been expressed in the form of a Boolean map in which excluded area being coded with a 0 and included area being coded with a 1.
In this study, the factors are (1) public transportation access, (2) proximity to job and service places, (3) waste management, (4) solar energy potential, and (5) independence of food production. Meanwhile, the constraints are (1) slope of the area, (2) geology of area, (3) proximity to waterbody, and (4) protected area. The ideal area of ecovillage (0.25-0.5 km²) is used in the later step.
Why “public transportation access” is considered as factor? Because the closer your ecovillage location to the public transportation, the better of it. The further, the worse of it.
Why “protected area” is considered as constraint? Because ecovillage cannot be built in the protected area, so this area is excluded.
Gather the raw data input
Sweden has an official website in which we can access a lot of data for GIS and Idrisi process. So, we gathered needed data, among others, study area, green corridor area, rail station, road, and digital elevation model. Some data are in vector or raster format.
Make the model to process the raw data
In here, we take a step further by processing the raw data into a data that will be used as an input in Decision Wizard. Many modules are used here, among others, “assign”, “buffer”, “pointras”, “lineras”, “distance”, “overlay”, “slope”, and “aspect”. Here is one of the example:
For geology data, assign module is used to generate Boolean map showing selected classes. Before, attribute value files is made to assign the old value to the new value. In this study, gravel, sand, till, and rock are assigned to 1 while clay, till, peat, and landfill are assigned to 0. The result is the constraint for geology.
For public transportation modes, analysis is made that the citizen of ecovillage use rail station and road for mobilization. That is why rail station and road data are used. After these data is converted into raster data using pointras module and lineras module, distance module is used to generate the distance. Developers identified areas within 50 m of roads or rail stations as the most suitable and areas beyond 50 m as having a continuously decreasing up to 1000 m.
Run the Decision Wizard
In Decision Wizard, factors, constraints, and generated data are used. For the Multi Criteria Analysis, AHP is used. In this study, two scenarios are generated: Scenario 1 put high score for public transportation modes while Scenario 2 put high score for proximity to job and service places. Why? We want to see the robustness of the result based on the main concern. Here is the final result (see the picture below). We still have to process it with modelling.
Choose the best site locations
In order to choose best site locations, we run a model by more or less using some modules among others, reclass, group, area, and overlay. In here, the ideal area of ecovillage (0.25-0.5 km²) is processed by using area module. Here is the final model.
Here is the result from the last models. Still not so understandable right? That’s why we have to process it further with GIS.
Visualize the final output with GIS
The way of how we visualize the final output is totally up to us. For further analysis, we can overlay the final output with geology layer to see the position of our sites along with the geology layer, and so on. Furthermore, we can analyze the size of each area, how many cells in each area, and so on. All in all, here is the final map of both scenarios.
So, it is super fun to see how Swedes plan their development right? 😀
It is full with system run in objective and comprehensive way. With this, we can get the best location while still keeping the sustainability. But, all in all, every model has its own uncertainties, limitation, and robustness. All of them has to be taken into consideration when stakeholders use this final result for decision making.