SDO_LRS.GET_PREV_SHAPE

Format

SDO_LRS.GET_PREV_SHAPE_PT(
     geom_segment IN SDO_GEOMETRY, 
     measure      IN NUMBER 
     ) RETURN SDO_GEOMETRY;

or

SDO_LRS.GET_PREV_SHAPE_PT(
     geom_segment IN SDO_GEOMETRY, 
     dim_array    IN SDO_DIM_ARRAY, 
     measure      IN NUMBER 
     ) RETURN SDO_GEOMETRY;

or

SDO_LRS.GET_PREV_SHAPE_PT(
     geom_segment IN SDO_GEOMETRY, 
     point        IN SDO_GEOMETRY 
     ) RETURN SDO_GEOMETRY;

or

SDO_LRS.GET_PREV_SHAPE_PT(
     geom_segment IN SDO_GEOMETRY, 
     dim_array    IN SDO_DIM_ARRAY, 
     point        IN SDO_GEOMETRY 
     ) RETURN SDO_GEOMETRY;

Description

Returns the previous shape point on a geometric segment before a specified measure value or LRS point.

Parameters

geom_segment: Geometric segment (LRS segment) containing measure information.
measure: Measure value on the geometric segment for which to return the previous shape point.
point: Point for which to return 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 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 Geometry Metadata Views).

Usage Notes

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, which returns 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_3D) is available. For information about _3D formats of LRS functions, see 3D Formats of LRS Functions.

Examples

The following example returns 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 Example of LRS Functions.)

SELECT SDO_LRS.GET_PREV_SHAPE_PT(a.route_geometry, 14)
   FROM lrs_routes a WHERE a.route_id = 1;

SDO_LRS.GET_PREV_SHAPE_PT(A.ROUTE_GEOMETRY,14)(SDO_GTYPE, SDO_SRID, SDO_POINT(X,
--------------------------------------------------------------------------------
SDO_GEOMETRY(3301, NULL, NULL, SDO_ELEM_INFO_ARRAY(1, 1, 1), SDO_ORDINATE_ARRAY(
12, 4, 12))