Dear Ignacio, thank you for your comment. I agree that data limitations, particularly in terms of consistent definitions and measures are of ongoing concern. At the city/municipality level, as you note, there are a number of mapping and data collection tools available for policy makers to better locate public services and facilities and to improve planning and investment to match areas of population growth. These are indeed important for improving city management and governance. Apart from that, what I think the literature reveals is that as we move higher in scale (from local to national to global) it becomes increasingly difficult to measure the nexus between urban spaces and urban populations in a consistent fashion. At this level, key questions are more broad; who/how many people are living in urban areas, and how much urban area is there? From then, we can look into the type and quality of services and amenities available, and which local government may be tasked to provide them.