One of our main interests at mappable is to find creative ways to use (geo-)data for mapping urban dynamics. In our newest project we will explore how phone directories can serve as a data source for various analytical tasks, starting with urban migration patterns.
For this purpose we bought German CD-ROM phone directories for the years 2004 – 2012 and exported all datasets for Berlin. We subsequently identified approximately 50.000 individual intra-city relocations and started to visualize and analyze the derived migration data. The first result of our work is an interactive, explorative visualization that let’s you explore Berlin’s intra-city migration patterns with high spatial granularity. You can take a closer look at it and explore the dataset on your own by clicking on the image bellow.
The migration patterns generated with our approach resemble those of the city’s official migration statistics. Thanks to the fact that our raw data are addresses, we are even able to analyze intra-city migration on a more detailed level than with the officially released data, which is aggregated to the county (‘Bezirk’)-level.
To sum things up: we are quite enthusiastic about the potential of phone directories as a data source and there are definitely more research questions that can be answered with these data sets besides only migration patterns (e.g. monitoring gentrification processes, identifying ethnicity patterns).
We will continue to publish short updates about this project here on our blog. If you want to take a more in depth look, see our project page, where you can find some words on how we processed the data, created the visualization and how we interpret the migration patterns we’ve found.
Finally, I found some time to continue working on my mapping tourism project. The first map I published some weeks ago displayed, as you might remember, every hotel & hostel in the city of Hamburg. The map hereby enabled the viewer to get an impression of the spatial dimension of tourism at a glance. Not bad as a starting point. But one of the main reasons tourism has become a topic of public interest in Hamburg recently, is the complaint by some inhabitants that growing tourism is becoming a problem in their neighborhood for various reasons (e.g. noise, traffic, littering). To address these issues too, it was necessary to include an additional aspect in my visualization: population. I’ve thus made a second map, which shows the ratio between inhabitants and tourists on a fine-grained level – in my eyes a very good indicator how ‘touristy’ an area is.
It was’n quite easy to find publicly accessible data for the map. The smallest existing tract shapes (German: statistische Gebiete) are provided by the city of Hamburg, which has opened up this data set as part of their recent open data initiative, which of course is a good thing. The down side is, that this data set is only available via an WFS-Server. A technique, which is not really suitable if you aim at opening up data for the average user. The population data comes from an official publication by the city of Hamburg, which unfortunately is only available as a pdf-Version, which meant quite some work for me to extract and process the data.
Finally having the data sets at hand, I calculated the number of tourists per area by spatially joining the hotel locations to each tract and counting the sum of provided rooms. The final visualization is once again done in CartDB – this time by using their API, which is way more flexible and allows you to integrate things like a switch between satellite-view and map-view. The final map makes it easy to see which are the most touristy parts of town (marked in blue). You can explore the interactive map by clicking here or on the preview picture below. Both lead to the updated project page, where I also added a new project summary (completely in English now).