What is data aggregation?

Aggregation in GIS means combining or summarizing geographic data at a higher level. Examples include counting points per district, averaging values per raster cell, or clustering many objects into one map symbol.

Aggregation makes large datasets manageable and supports regional or national decision-making. In dashboards, BAG data may be aggregated per municipality; in raster analysis, DEM cells are averaged per area.

Aggregation is no longer raw data: detail is traded for patterns and totals. The aggregation level (parcel, neighborhood, municipality) determines what insights appear and must match the question.