What does "completely within" select when choosing by location?

The concept of "completely within" in the context of selecting features by location in a Geographic Information System (GIS) refers to a specific spatial relationship where the source feature must entirely fit within the boundaries of the target feature. This means that every part of the source feature is contained inside the target feature without extending beyond it.

For example, if you have a polygon representing a park (the target feature) and a polygon representing a building (the source feature), for the building to be considered "completely within" the park, it should not touch or extend outside the park's boundaries; all points of the building polygon must reside inside the park polygon.

This spatial relationship is crucial for various analyses such as land use planning, environmental impact assessments, and urban planning tasks where knowing the exact containment and relationships of features is important for decision-making and spatial data analysis. Understanding this concept helps in correctly applying selection criteria in GIS to gather relevant data sets for any analysis.