Land data improves accessibility

Cadastral planning, urbanism, property values, and risk maps have made land more readable from an office setting than ever before. This increased accessibility, however, comes with blind spots where critical project decisions are often made.

Cadastral plans provide basic info

The cadastral plan, accessible through the government's cadastral service and the IGN mapping services, provides a shape, size, position in relation to roads and neighboring parcels, and a reference for locating the plot in other databases. However, it is a fiscal document and does not fix property boundaries or list owner names, only a survey by a licensed surveyor can define a plot.

Urban planning documents online

The Urbanism Géoportail serves as the national, online, and unique access point to urban planning documents and public utility servitudes. It allows users to read the applicable zoning, download written regulations, identify graphical prescriptions, and locate reserved areas and overlapping zones.

Property values are now public

Property values are now publicly accessible since 2018, with the administration required to make property transfer values from the last five years freely available in electronic form. This includes dates, prices, addresses, cadastral references, and some areas and property types.

Data gaps remain in public records

Despite these data sets, several aspects remain unaddressed. Public utility servitudes may not all be included in the same location, and some may be in the paper annex of a file without being on the online map. Private servitudes, such as rights of passage or water drainage, are found in property titles and published acts, not in geoportal layers.

Regulations require interpretation

Regulations are not always straightforward. Quantifiable rules like maximum height or footprint coefficients can be extracted, but rules on external appearance, landscape integration, and coherence with surrounding buildings require interpretation, which is not provided by software or architects alone. This interpretation is negotiated with instructing services and sometimes the Architect of the French Buildings, a process not recorded in databases.

Urbanism certificate offers stability

The urbanism certificate, required when submitting a project for a state service's opinion or agreement, mentions these considerations explicitly. It freezes current rights for eighteen months, benefiting a request deposited within that period, except for safety or public health provisions. This certificate is not a building permit but offers stability that no data reading can provide.

Data cannot capture all factors

Public data cannot capture all factors affecting a parcel. Property values indicate prices but not reasons, such as pollution, isolation, leases, or neighbors buying land for expansion. Risk maps note known hazards but not soil conditions, which require geotechnical studies.

Project reading is essential

There are two readings of a parcel: a systematic reading that crosses sources and applies quantifiable rules, and a project reading that starts from an intention and searches for margins within the rules. The systematic reading is fast and reproducible but limited to digitized data. The project reading, which transforms constraints into design, cannot be automated and is essential for meaningful development.

Data shift architect's role

Public data have made parcels readable before a sketch, but they have not made the sketch unnecessary. They shift the beginning of an architect's work to an earlier stage with more complete information, emphasizing the responsibility of knowing what data omit.