7.2 LRS Data Model

The Oracle Spatial LRS data model incorporates measure information into its geometry representation at the point level.

The measure information is directly integrated into the Oracle Spatial model. To accomplish this, an additional measure dimension must be added to the Oracle Spatial metadata.

Oracle Spatial LRS support affects the spatial metadata and data (the geometries). Example 7-1 shows how a measure dimension can be added to two-dimensional geometries in the spatial metadata. The measure dimension must be the last element of the SDO_DIM_ARRAY in a spatial object definition (shown in bold in Example 7-1).

Figure 7-7 Creating a Geometric Segment

Description of "Figure 7-7 Creating a Geometric Segment"

In Figure 7-7, the geometric segment has the following definition (with measure values underlined):

SDO_GEOMETRY(3302, NULL, NULL,
     SDO_ELEM_INFO_ARRAY(1,2,1),
     SDO_ORDINATE_ARRAY(5,10,0, 20,5,NULL, 35,10,NULL, 55,10,100))

Whenever a geometric segment is defined, its start and end measures must be defined or derived from some existing geometric segment. The unsigned measures of all shape points on a geometric segment will be automatically populated.

The SDO_GTYPE of any point geometry used with an LRS function must be 3301.

Example 7-1 Including LRS Measure Dimension in Spatial Metadata

INSERT INTO user_sdo_geom_metadata
    (TABLE_NAME,
     COLUMN_NAME,
     DIMINFO,
     SRID)
  VALUES(
  'LRS_ROUTES',
  'GEOMETRY',
  SDO_DIM_ARRAY (
    SDO_DIM_ELEMENT('X', 0, 20, 0.005),
    SDO_DIM_ELEMENT('Y', 0, 20, 0.005),
    SDO_DIM_ELEMENT('M', 0, 100, 0.005)),
  NULL);

After adding the new measure dimension, geometries with measure information such as geometric segments and LRS points can be represented. An example of creating a geometric segment with three line segments is shown in Figure 7-7.