"Portion Heatmap" - Fragmentation of Domestic Space in 1808 Venice.

This thematic map visualizes the frequency of the word “portion” in the cadastral dataset, as it appears in the “Quality” field alongside urban functions. The most common phrase is “portion of house”, pointing to a striking phenomenon in the structure of the built environment: the internal fragmentation of housing units.

These "portions" typically refer to parts of a single building—often individual floors—owned by different individuals. This suggests that buildings originally constructed as unified homes were later subdivided into multiple residential units, likely to accommodate several households within a constrained urban fabric.

The pattern becomes even more significant when considering the number of distinct owners per parcel. In some cases, the heatmap reveals eight or more owners for properties that consist of only two or three floors. This degree of subdivision indicates a form of micro-property ownership, possibly reflecting economic strategies to enable families of modest means to access urban housing through partial acquisition or rental arrangements.

The map thus highlights not only a spatial pattern, but also a social and economic adaptation: a city responding to demographic pressure and evolving needs by reconfiguring its interior domestic space—layer by layer, owner by owner.