Basic concepts

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A bounding box-processing operator checks whether the bounding boxes of two spatio-temporal objects satisfy a specified spatio-temporal relationship. Each operator combines an operator mark with optional dimension marks that control which dimensions are compared. By default, an operator without dimension marks compares objects in the x and y dimensions only.

Operator marks

The following operator marks are supported:

SymbolRelationship tested
&& or &INTERSECT — do the two bounding boxes intersect?
@>INCLUDE — does the left bounding box contain the right one?
<@INCLUDED — is the left bounding box contained by the right one?

Dimension marks

To extend or restrict the comparison to additional dimensions, add one or both of the following dimension marks to the operator:

SymbolDimension
/z dimension
#t dimension

Dimension mark placement rules:

  • Between the operator marks — the operator compares objects in that dimension in addition to the x and y dimensions.

  • On both sides of the operator mark — the operator compares objects only in that dimension, and does not compare objects in the other dimensions, such as the x and y dimensions.

When both dimension marks are present, the z dimension mark precedes the t dimension mark.