7.4 3D Formats of LRS Functions

Most LRS functions have formats that end in _3D: for example, DEFINE_GEOM_SEGMENT_3D, CLIP_GEOM_SEGMENT_3D, FIND_MEASURE_3D, and LOCATE_PT_3D. If a function has a 3D format, it is identified in the Usage Notes for the function’s reference topic.

The 3D formats are supported only for line string and multiline string geometries. (They are not supported for polygons, arcs, or circles.) The 3D formats should be used only when the geometry object has four dimensions and the fourth dimension is the measure (for example, X, Y, Z, and M), and only when you want the function to consider the first three dimensions (for example, X, Y, and Z). If the standard format of a function (that is, without the _3D) is used on a geometry with four dimensions, the function considers only the first two dimensions (for example, X and Y).

For example, the following format considers the X, Y, and Z dimensions of the specified GEOM object in performing the clip operation:

SELECT  SDO_LRS.CLIP_GEOM_SEGMENT_3D(a.geom, m.diminfo, 5, 10)
  FROM routes r, user_sdo_geom_metadata m
  WHERE m.table_name = 'ROUTES' AND m.column_name = 'GEOM'
    AND r.route_id = 1;

However, the following format considers only the X and Y dimensions, and ignores the Z dimension, of the specified GEOM object in performing the clip operation:

SELECT  SDO_LRS.CLIP_GEOM_SEGMENT(a.geom, m.diminfo, 5, 10)
  FROM routes r, user_sdo_geom_metadata m
  WHERE m.table_name = 'ROUTES' AND m.column_name = 'GEOM'
    AND r.route_id = 1;

The parameters for the standard and 3D formats of any function are the same, and the Usage Notes apply to both formats.

If the parameters for an LRS function include both a line (or multiline) string and a point (LRS point), both the line string and the point must have the same number of dimensions. For example:

• For the SDO_LRS.PROJECT_PT function, the input geom_segment (line) must have two dimensions (X.Y) plus the measure dimension, and the the input point point must be a two-dimensional LRS point geometry with a measure dimension (SDO_GTYPE = 3301). (This is the case in the example for that function.)

• For the SDO_LRS.PROJECT_PT_3D function. the input geom_segment must have three dimensions (X,Y,Z) plus the measure dimension, and the input point point must be a three-dimensional LRS point geometry with a measure dimension (SDO_GTYPE = 3401).