7.3 Indexing of LRS Data
If LRS data has four dimensions (three plus the M dimension) and if you need to index all three non-measure dimensions, you must use a spatial R-tree index to index the data.
You must also specify PARAMETERS('sdo_indx_dims=3') in the CREATE INDEX statement to ensure that the first three dimensions are indexed. Note, however, that if you specify an sdo_indx_dims
value of 3 or higher, only those operators listed in Three-Dimensional Spatial Objects as considering all three dimensions can be used on the indexed geometries; the other operators described in Spatial Operators cannot be used. (The default value for the sdo_indx_dims
keyword is 2, which would cause only the first two dimensions to be indexed.) For example, if the dimensions are X, Y, Z, and M, specify sdo_indx_dims=3
to index the X, Y, and Z dimensions, but not the measure (M) dimension. Do not include the measure dimension in a spatial index, because this causes additional processing overhead and produces no benefit.
Information about the CREATE INDEX statement and its parameters and keywords is in SQL Statements for Indexing Spatial Data.
Parent topic: Linear Referencing System