See the following topics for more information including how to setup and review Base and Alt. LRMs:

Data Model

Once the alternate referencing is defined in the SETUP_LOC_REF_COLUMNS table and the changes applied to the database, the columns configured there will appear in the SETUP_LOC_IDENT table (refer to Chapter 4, for in-depth understanding and information about other uses of this table). In order to support translation between the base and Alt. LRMs, as shown in the following figure, the system requires a full map between them.

The mapping between the base and alternate is provided by a special set of rows in the SETUP_LOC_IDENT table. These rows are always identified by the row filter: SOURSE_TABLE='LOC_REF_XX' (where XX is the ID number of alternate referencing system from SETUP_LOC_REF).

This set of rows in SETUP_LOC_IDENT must always be a full map between all references in the alternate system mapped onto the base system. When editing and viewing data the system utilizes these records to calculate a base reference when given an alternate and vice versa. The example in the next section shows as an example. Records corresponding to the table SETUP_LOC_IDENT – LOC_REF_25 Sourse_Table are displayed (in this example, LOC_REF_ID for the Alt. LRM is 25). The LOC_IDENT is a unique identifier in this table and contains information about each route segment mapping between the Base and Alternate Referencing System – Attribute Columns (Route Number, County, Direction, Functional Class, etc.) and the Measure Columns (State-wide Milepost From/To, etc.).


There is no Alt LRM configured out of the box, but if you have created an Alt LRM, when you right-click the record for an alternate LRM in the upper pane, the system displays the following special command in a shortcut menu:

  • Make Window – This command will create a new window that shows the mapping between Base and Alt. LRM. After choosing this command, a pop-up window (Form Window Maker) will display. Choose the "Alternative location Editor" and click Next. Then click the parent menu item into which a menu item for the window, which will show the cross-reference table between the Basic Referencing System (BRS) and the selected alternate system. After selecting the parent menu item, click OK to close the window. Then log off and log back on, and the menu item will be in the designated place, with the name of the menu item being what is entered in the Loc Ref Name column. Open the new window to see the cross-reference table. The BRS is shown on the left and the alternate system is on the right. User can then use the window to enter the mapping between the Base and Alt. LRM.

The steps are shown in the following charts.

Add a menu item under this parent

Example Alternate LRM Mapping Screen

SETUP_LOC_IDENT Table Data with a County-Based LRM Example

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