Oracle Spatial User's Guide and Reference - InfoLab

Parameters
Usage Notes
Examples
geom_segment
Geometric segment.
SDO_LRS.GET_PREV_SHAPE_PT_MEASURE
measure
Measure value on the geometric segment for which to return the measure value of
the previous shape point.
point
Point for which to return the measure value of the previous shape point. If point is
not on geom_segment, the point on the geometric segment closest to the specified
point is computed, and the measure value of the closest shape point before that
point is returned.
dim_array
Dimensional information array corresponding to geom_segment, usually selected
from one of the xxx_SDO_GEOM_METADATA views (described in Section 2.4).
If measure or point identifies the start point of the geometric segment, a null
value is returned.
An exception is raised if measure is not a valid value for geom_segment or if
point is not a valid LRS point.
Contrast this function with SDO_LRS.GET_NEXT_SHAPE_PT_MEASURE, which
returns the measure value of the next shape point on a geometric segment after a
specified measure value or LRS point.
The _3D format of this function (SDO_LRS.GET_PREV_SHAPE_PT_MEASURE_
3D) is available. For information about _3D formats of LRS functions, see
Section 7.4.
The following example returns the measure value of the closest shape point to
measure 14 and before measure 14 on the geometric segment representing Route 1.
(This example uses the definitions from the example in Section 7.7.)
SELECT SDO_LRS.GET_PREV_SHAPE_PT_MEASURE(a.route_geometry, 14)
FROM lrs_routes a WHERE a.route_id = 1;
SDO_LRS.GET_PREV_SHAPE_PT_MEASURE(A.ROUTE_GEOMETRY,14)
Linear Referencing Subprograms 16-59