Urban retail follows similar logics in cities, even if they are not multimillion metro areas. I will talk now about the city I have lived in for 30 years. Coruña, in northwestern Spain, is the second most densely populated municipality in Spain; with sligthly less than 250.000, it is the center of a metro area of about half a million people, has a busy harbor oriented towards oil, and in the next municipality to the west are the world headquarters of Zara, the apparel merchant, whose first shop was here (I happened to pass by as a kid, not suspecting it would become such a world company…)
Just in order to give an impression of how dense the city fabric is, in what many would not identify as Spain, as the landscape is closer to that of Britanny, for instance, two views. The historical city is on a narrow penninsula that creates a safe bay, the reason for the city location.

Zone C on the map, Ronda de Outeiro, as seen from A. The high densities of the 1960s and 1970s, continued today
The maps in this post are based on the cadastre databases, as manipulated in an open source GIS. This source offers the advantage of giving areas for the different land uses, to a large degree of detail; they also have two problems: they indicate someone is paying land taxes for the different housing units and other uses inside each building (a relevant feature in a country in which multistorey buildings are a normal feature in cities), but not if the space is being really used for that specific purpose, as the case for vacant shops, and they can have, as in any database of such size, some errors. The maps show densities, so sometimes a white value does not mean the lack of the feature, but the lack of weight as compared to other zones.
Anyway, what those maps show is that even in an extremely dense city there is no mathematic correlation between global density and shops density. The values are somehow biassed by the lack of habit in this particular city to have the ground floor used for housing, as generally it is sold for shops (they are theoretically viable with such a number of potential clients around), but there are clear commercial centralities (which will be shown in tomorrow’s post).
The density of housing units is quite high, but specially southwest of the central city, in the Ronda de Outeiro area, and in the growth areas from the 1960s/ 1970s (even today, densities are extremely high by normal spanish standards)
The retail surface by building lots map shows that you have a light hue (small surface shops) “banana” in the isthmus, and a set of large “dots” corresponding to peripheral commercial centers and big box retail.
The built up area by lot map is similar to the housing density map, as most uses in the represented area are residential.
The distribution of the number of retail establishments by lot is similar to the distribution of retail surfaces, with a clrea difference: the large peripheral centers have either a more reduced number of cadastral units (they can be on rent, with the same owner) or there can be a delay in their introduction in the database for the more recent.