A location is not a version
A location can remain the same while almost everything relevant to an intervention changes. A pavement is resurfaced, a cabinet is moved, an access route is closed or a temporary installation becomes permanent. The map still points to the right place. The operating description may no longer describe what the team will find there. A useful urban record therefore needs more than coordinates. It needs a date, a condition, a source and a way to distinguish the current view from the evidence that preceded it.
The phrase versioned city does not imply that a street can be restored with a software command. Physical changes have costs and consequences that a database cannot reverse. It means that the record should preserve enough sequence to explain why today's representation differs from yesterday's. When an inspection contradicts the register, overwriting the old value may remove the clue needed to understand the discrepancy. Retaining both observations, with a resolution status, allows the team to work through the disagreement without pretending it never existed.
Three kinds of change
The first kind is a change to the asset itself: a component was replaced, a surface repaired or an assembly reconfigured. The second is a change in what is known: a previously hidden condition was observed or a location was measured more accurately. The third is a change in classification: the organisation revised how it groups interventions or defines closure. These changes can produce similar movements in a table, but they should not be reported as the same event. Only the first necessarily describes a physical intervention.
Consider a hypothetical maintenance record whose status moves from open to closed. The work may have been completed. Alternatively, a duplicate request may have been removed, or a classification rule may now place that request outside the reporting perimeter. A quarterly chart that treats all three as completed work will tell a misleading story. The underlying event needs a type and a reason. A method revision should appear in the review as a method revision, even when it makes the headline indicator less convenient to compare.
Keep the field observation intact
For Meridian, the proposed review unit is the link between an inspection observation and the intervention that follows. The inspection record should retain what was observed, when, by whom and under which limitations. The planning record can then classify the response without rewriting the observation to fit the chosen action. If work is deferred, that decision belongs beside the observation. It should not make the original condition disappear. This separation helps a later reviewer distinguish an overlooked defect from a consciously scheduled intervention.
Verdan's technical-study work raises a related issue. A design drawing, a survey observation and an approved project boundary can describe the same area without having the same authority. Their relationship needs to be explicit. The W3C PROV framework is a useful conceptual reference because it connects information with the activities and agents involved in producing it. The portfolio application is more modest than a universal city model: each important record should identify its source and the action that produced or revised it. That is enough to make many disagreements investigable.
A surface that can be maintained
A drawing's date should also distinguish the date of survey from the date of publication. A recently exported file can contain an old observation. The operating view needs both dates when that difference affects the next intervention.
PRIMA makes the issue visible at the scale of a façade. A matrix may have one geometry in a design study and another after site integration. Individual tiles may later be replaced, while the visible composition remains similar. The source drawing, installed configuration and maintenance history should therefore have separate identities. A new content sequence is another kind of change again. It must not be confused with a physical alteration to the assembly. These distinctions should be defined before a prototype becomes an operating installation.
The next useful improvement is a small one: select a representative asset record and reconstruct its sequence without asking the original author to explain it. Can the reviewer identify the current condition, the superseded drawings, the last physical change and the last methodological change? Where that sequence breaks, add the missing relation rather than another summary field. A city is continuously revised by work and by knowledge. Its information systems become more credible when they show those revisions clearly enough for the next team to act on them.
Sources and data notes
- W3C — PROV Overview2013 · Reference for connecting data entities with activities and responsible agents.