select_region_spatial — Pose relation of regions.
select_region_spatial chooses the regions from
which are sufficient for the neighboring relation
The regions to be examined have to be passed in
Regions1 can have
three different states:
Possible values for
Regions2 is left of
Regions2 is right of
Regions2 is above
Regions2 is below
select_region_spatial calculates the centers of the regions to be
compared and decides according to the angle between the center straight lines
and the x axis whether the direction relation is fulfilled.
The relation is fulfilled within the area of -45 degree to +45 degree
around the coordinate axes.
Thus, the direction relation can be understood in such a way that the center
of the second region must be located left (or right, above, below) of
the center of the first region.
The indices of the regions fulfilling the direction relation are located
at the n-th position in
i.e., the region with the index
RegionIndex2[n] has the indicated
relation with the region with the index
Access to regions via the index can be obtained via the operator
Desired neighboring relation.
Default value: 'left'
List of values: 'above', 'below', 'left', 'right'
select_region_spatial returns the value TRUE if
Regions2 is not empty. The behavior
in case of empty parameter
Regions2 (no input regions available)
is set via the operator
The behavior in case of empty region (the region is the empty set) is set via
If necessary an exception is raised.