Built-Up Density

Built-up density is important for planners like us. I remember when I made my final project titled Urban Fire Risk in Bandung. In my final project, one of the criteria to derive the risk index was by employing “population density”. The main problem is that this data were come in regional based, which mean it does not contigious and not so reliable. Population density every where in Indonesia is based on Kelurahan (village administrative unit). Density is caunted firstly by summing the population per village and divided with the total area of the the correspond village.

I read many article try to solve this problem by applying other demography instrument, one of it is by using built-up density. Built-up density is based on a though that population living in area must have a linier correlation with the place where he/she lives. In other words, buil-up density must have reflects the population density. The higher the population density, the more higher built-up density, or vice versa.

then, our question is, how to make the built-up density? simple. First think that you should have are;

1. installed ArcView and ArcGIS 8/9 with Spatial Analyst extention checked in your computer
2. Land use data in vector based
3. I use Xtools, additional tools for ArcView 3.3

How to make it? I will explain you the logic thinking behind all these functions before we go step-by-step through the functions. OK, the key is we will make the built-up density by using “density” function from spatial analyst ArcGIS. this function requires you to have vector point input WITH the value attached on to it. Suppose, the value of the point is the size (in hectare) of your built-up area.

then, the next question is, how to make vector point? Simple. first you have to view your land use vector layer. then, select all your built-up area including for example, stadium, school, commercial, and industrial. Use select wizard from ArcGIS/View to make your live easier. Make your selection into new layer and named it “built-up”. After you are sure you have separated the built-up area from other land uses, then now calculate the area of your built-up area polygons by using “calculate perimeter, area” from XTools ArcView.

Next step, open your ArcView and display your built-up layer. Then convert this polygon into vector point by using XTools “convert shapes into point”. Voila!!, now you already have an input for “density” functions. Go through density function in ArcGIS and choose your optimum searching area.

Any question can be posted in comment coulomn.

Thnx