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LRS Operations
For examples of these operations, see the Usage Notes and Examples for the SDO_
LRS.TRANSLATE_MEASURE, SDO_LRS.REVERSE_GEOMETRY, and SDO_
LRS.REDEFINE_GEOM_SEGMENT subprograms in Chapter 25.
7.5.7 Offsetting a Geometric Segment
You can create a new geometric segment by performing an offsetting operation on a
geometric segment. Figure 7–14 shows the mapping relationship for geometric
segment offsetting.
Figure 7–14 Offsetting a Geometric Segment
In the offsetting operation shown in Figure 7–14, the resulting geometric segment is
offset by 5 units from the specified start and end measures of the original segment.
For more information, see the Usage Notes and Examples for the SDO_LRS.OFFSET_
GEOM_SEGMENT function in Chapter 25.
7.5.8 Locating a Point on a Geometric Segment
You can find the position of a point described by a measure and an offset on a
geometric segment (see Figure 7–15).
Figure 7–15 Locating a Point Along a Segment with a Measure and an Offset
Start Point
There is always a unique location with a specific measure on a geometric segment.
Ambiguity arises when offsets are given and the points described by the measures fall
on shape points of the geometric segment (see Figure 7–16).
7-12 Oracle Spatial Developer’s Guide
Direction of the Segments
Start Measure
Resulting Segment
Positive Offset
(for example, 5)
Negative Offset
(for example, -5)
End Measure
Segment Direction
Projection Point
Measure
Positive Offset
Negative Offset
End Point
Offset (Positive if to left along segment direction;
negative if to right along segment direction.)
Point to Be Located