/ Filters / Chapter 35. Using spatial properties of features in filters / Distances between featuresTo define Minimum Distance and Maximum Distance properties it is required to specify a relation variant clarifying the sense of the relation on matching the given (tested) feature with a set of argument features. Relation variants which can be used with these properties are shown in the table 35-2.
Relation variant | Simple condition truth terms |
Any | The given relation is satisfied for distance from the tested feature to at least one argument feature. |
Each | The given relation is satisfied for distances from the tested feature to each argument feature. |
Sum | Sum of distances from the tested feature to all argument features is evaluated, and the given relation is checked for this sum. |
Average | The evaluated sum is divided by total number of argument features, and the given relation is checked for this average value. If the number of argument features is zero, the relation is considered to be false. |
Minimum | Minimum value of distance (minimal or maximal) from the tested feature to each argument feature is evaluated, and the given relation is checked for this minimum. |
Maximum | Maximum value of distance (minimal or maximal) from the tested feature to each argument feature is evaluated, and the given relation is checked for this maximum. |
Table 35-2. Relation variants for minimum and maximum distance relations
The relation variants Minimum and Maximum are not to be confused with names of properties Minimum Distance and Maximum Distance.
Evaluating property Minimum (Maximum) Distance is executed separately for each argument feature, and minimum or maximum is sought on sets of all points of tested feature and argument feature.
Otherwise, on evaluating relation variants Minimum and Maximum the calculated values for each feature from the set of all argument features are considered, and minimum or maximum is sought on this set.
The figure 35-6 illustrates the aforesaid.
Figure 35-6. Minimum and Maximum variants for distance properties
Minimum distances from line tested feature T to line argument feature A1 and A2 equals 2 and 3, correspondingly. Hence for the property Minimum Distance and variant Minimum the specified comparison or diapason/interval relation will be checked for the value 2, and for the variant Maximum it will be checked for the value 3.
Maximum distances from tested feature T to argument feature A1 and A2 equals 9 and 8, correspondingly. Hence for the property Maximum Distance and variant Minimum the specified relation will be checked for the value 8, and for the variant Maximum it will be checked for the value 9.
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