Union vs Intersect in QGIS: how to use and what's the difference

Differences between union and intersect analytical operations explained

In this tutorial about QGIS 3 I’ll show you two useful operators for vector data: UNION and INTERSECT.

Union vs Intersection

In GIS, a union is an analytical process in which the features from two or more map layers are combined into a single, composite layer. Union includes the data from all the included layers, meaning that overlapping and non-overlapping areas are included in a new polygon.

An Intersect is an analytical operation that can be used to select any part of a feature that intersects with one or more other features. The areas of the map where all the input features intersect will create a feature as the intersect output.

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