Urban change

Detecting building and urban change with GeoAI

Published · Updated · 7 min read · Mapizy Insights Team

Building footprints and urban change in aerial imagery

An accurate building footprint is only useful if it is current. Change maps tell teams what was added, removed, or altered between image dates.

Real-estate, insurance, and government users need up-to-date building footprints and change maps. Mapizy uses high-resolution aerial and satellite imagery to create building-footprint data with a stated three-month currency, then applies deep learning to detect footprint change for compliance, valuation, and disaster assessment.

Key takeaways

Product

Building footprint

GIS-ready footprints derived from aerial and satellite imagery, described as globally available packaged data.

Currency

Three months

Packaged footprint data is positioned as the most up-to-date available when needed, with a three-month update cycle.

Signal

Change maps

Deep-learning change detection supports adverse-possession checks, approved-plan compliance, and disaster damage review.

Scale

Parcel to suburb

Urban Analytics tracks urban growth, vegetation cover, and property counts so local change sits in a wider context.

Methodology

1

Map the built form

Extract building outlines from the latest high-resolution imagery rather than relying only on older cadastre or mapping layers.

2

Compare dates

Run change detection between image epochs so new, removed, or expanded buildings become a map, not a guess.

3

Roll up

Use suburb and LGA analytics for growth rate, inventory, and notification of property changes that affect rates or policy.

Illustrative before and after building change Two panels showing a street block before and after a new building outline appears. Earlier image Later image Illustrative comparison. Pink marks a conceptual new footprint, not a measured rate.
Conceptual before/after building change. This graphic is illustrative.

Where change maps are used

Real estate and compliance

Updated footprints help check potential adverse-possession claims and whether built form still matches approved plans. History of property change also feeds more grounded valuation.

Insurance and government

Insurers need change maps after bushfire and flood. Councils can update geospatial databases more frequently and get notified of property changes that affect rates and compliance. See Government and Building Footprint.

Sources and limitations

Statements about currency, coverage, and change detection come from Mapizy’s packaged-data, use-case, and industry pages. No customer hit-rate or accuracy percentage is claimed here. Image alignment, occlusion, and date gaps remain real constraints. Diagrams are conceptual.

Related reports

Review footprint and change data

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