Parcel Data Aggregation
Definition
Parcel data aggregation combines cadastral records from multiple jurisdictions into a standardized dataset for analysis or publication. Challenges include inconsistent schemas, varied coordinate systems, different vintages, and privacy rules. Aggregation requires schema harmonization (field crosswalks), geometry validation, deduplication, and versioning. Attributes may include parcel IDs, land use codes, assessed values, and area. Because parcels carry legal implications, aggregated products should be labeled non-authoritative and include links back to original sources. Aggregation unlocks national-scale studies of property patterns, housing supply, and infrastructure planning while reducing duplication of effort across agencies and companies.
Application
National portals compile parcels for planning and taxation studies. Utilities overlay assets with parcels across service territories. Researchers analyze fragmentation and vacancy. Real-estate analytics standardize parcels for valuation models. Emergency managers integrate parcels with hazards for rapid impact estimates.
FAQ
How do you manage differing coordinate systems?
Reproject to a common CRS with explicit datum transformations, preserving original coordinates as attributes for traceability.
What about parcel IDs that aren’t unique nationwide?
Create composite keys with jurisdiction codes; maintain lookup tables to original IDs for back-referencing and legal checks.
How to respect privacy and legal constraints?
Publish minimal personally identifiable information, follow local laws, and clearly mark authoritative sources and usage limits.
How to handle overlaps and gaps between counties?
Define precedence, reconcile edges with surveys where possible, and flag unresolved conflicts for source agencies to review.
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