Reachability Analysis for two locations

A company was faced with the decision to either open a new branch in Bamberg or Coburg and asked Geofabrik to back the decision with information about the reachability of these two cities by car and the number of inhabitants in the area around these two cities. They wanted to know

To answer these questions, reachability polygons were computed using Geofabrik Spider Graph for both Coburg and Bamberg. The rings (10 minute interval) around both cities were merged in order to see which regions are more than n minutes aways from any of the cities. By intersecting the polygons, it was determined which areas have an almost equal distance to both cities. The results can be seen in the following map.

Select overlay:

To answer the questions which involve population data, the dataset Bevölkerung im 100 Meter-Gitter (population in a 100 meter grid), a result of the 2011 European Union census in Germany, was used. The dataset is available as a CSV file under the Data Licence Germany Attribution Version 2.0. It was imported into a PostGIS database and intersected with the polygons. The intersection resulted in the following table:

DestinationTravel time (minutes)inhabitantssum
Bamberg10 92 199 92 199
Bamberg20103 056 192 255
Bamberg30141 560 336 815
Bamberg40792 1251 128 940
Bamberg50704 3511 833 291
Bamberg60320 4812 153 772
Coburg10 52 730 52 730
Coburg20 56 360109 090
Coburg30126 854235 944
Coburg40228 382464 326
Coburg50256 347720 673
Coburg60174 439895 112