Geographical hierarchy explains how places or properties fit together into a simple-to-understand and ordered structure.
Geographical hierarchy is a common concept we use every day. The application of it is the interesting part.
Every street address lives inside of a hierarchy. A street address is housed inside of a suburb, which is located inside of a city / town, which is located normally inside of a province, which is contained by a country. And countries live in continents, which are located in the world. And so it goes.
Each of these hierarchy levels is a container of sorts. And these containers, plotted on a map, are polygons. In turn, these polygons are defined by co-ordinates. The number of points in a polygon equals the number of co-ordinates that defines the polygon.
Geographical hierarchy applied to point data
Thus, if your hierarchical data structures are correctly built. It should be possible, for any one co-ordinate on a map, to build out a complete story of where that point lives. For example:
- Enter: co-ordinate
- Output: co-ordinate –> assign co-ordinate to erf –> assign co-ordinate (living inside erf) to suburb –> assign co-ordinate (living inside suburb) to city / town –> assign co-ordinate (living inside suburb) to city/town –> assign co-ordinate (living inside city/town) to province
More info on polygons
Polygons are interesting and powerful.. Some are created subject to commonly-accepted convention, such as countries. Others can represent a specific person, business or project’s view of an area.
- A polygon representing a desired area north of Johannesburg for the purposes of an office customer relocating
- A polygon representing a level in between suburb and city / town, that represents a collection of suburbs – for example Cape Town Southern Suburbs
Applying these concepts can change the way you think about approaching problems, and give you a lot more power and flexibility in solving customer problems / giving customer solutions.
For more reading
Please see this article courtesy of RICS.