The same charts and the same rules applied to each national register. Which countries take part, and in which panels, is set in the file shared by the twin sites.
Share of dated buildings by construction century (%). Two opposite profiles: France protects mostly the 12th to 18th c., Portugal the 16th to 20th.
Protection acts per decade. The series do not measure the same thing everywhere: see the caveats under the framing table.
Share of sacred (religious and funerary) among the century’s dated buildings. Aggregate: France 38.4% and Portugal 39.2%, near twins.
Persons present in BOTH registers (surname and given name). Gustave Eiffel and Oscar Niemeyer built protected heritage on both sides.
Each point is a Getty AAT concept present in BOTH national vocabularies (FR 740 anchored terms, PT 721); the axes are each register’s share. 130 shared concepts, 49 with 10 or more monuments on each side.