Documenting Heritage at Territorial Scale: Heritage Building Information Modelling–Geographic Information System Integration (GeoBIM) and an Effort Unit for Scalable Multiscale Documentation Through Remote Sensing—The DIGIBIC Model (Extremadura)

Territorial heritage documentation programmes require coordinated acquisition, processing and information management across assets with different documentation demands. This study presents the Equivalent Documentation Unit (UDE, retaining the project acronym from the Spanish Unidad de Documentación Equivalente), defined as one normalized active person-day of eight person-hours, within the DIGIBIC HBIM–GIS workflow in Extremadura, Spain. The framework distinguishes estimated workload, recorded labour consumption and accepted deliverables. Eighteen development cases document workload heterogeneity and inform a preliminary expert-sizing procedure structured by asset descriptors. Recorded effort in this cohort ranges from 3 to 26 UDEs per asset. Six non-overlapping DIGIBIC 2.0 cases support a retrospective descriptive comparison of expert estimates with an equal-allocation comparator for completed, comparable tasks. For total effort, expert estimates yield a mean absolute error of 1.333 UDEs and a root mean square error of 1.732 UDEs, compared with 1.167 and 1.607 UDEs for equal allocation. In these six cases, field-effort errors are lower under expert sizing, whereas office-effort errors show no corresponding improvement. The contribution is an operational framework linking documentation scope, effort records and territorial information products. The observed estimation errors identify office-work sizing as a priority for refinement and motivate further assessment using new cases.