See the second chapter of my project Transportation Data Analysis.
Barcelona parcels colored by block population.
See the map
A map that shows bus lines & stops. Selecting the stop you can check real time bus schedules
I just published a map that shows the distance (in meters) amongst the so called “Kilometer Zero” (Puerta del Sol) and most of the public squares (Plazas) in Madrid. The data comes from Madrid´s Open Data website. You can find the calculation process here and below the resulting interactive interface, that allows to filter distances and navigate using zooming and panning features.