Performing a Best Route Analysis
 Concept Procedure Quick Reference

NoteThis procedure applies only to drawing objects.

To perform a best route analysis

1. Verify that you have a network topology available and it is loaded. See Creating Topologies and To load a topology.
2. In Map Explorer under Current Drawing, right-click a network topologyAnalysisNetwork Analysis.
3. In the Network Topology Analysis - Select Method dialog box, click Best Route. Click Next.
4. In the Network Topology Analysis - Choose Locations dialog box, click Start Point. Click Select Point to select the starting point in the drawing. Press Enter to return to the dialog box.

AutoCAD Map 3D uses the node closest to the location you clicked as the start point. The coordinates of the point are shown in the list.

5. Click Visit Point. Click (Select Point).
6. In the drawing, click a point to visit during the best route analysis. It does not matter which point you pick first, AutoCAD Map 3D calculates the order in which to visit the sites as part of the calculation.

AutoCAD Map 3D uses the node closest to the location you clicked as the visit point.

7. Do one of the following:
• To accept the point and return to the dialog box, press Enter.
• To discard the point and return to the dialog box, press Esc.
• To accept the point and specify another point, right-click in the drawing. Click Next Point.
8. In the dialog box, review the start points and visit points you have specified.
• To double-check the location of a point in the map, highlight the coordinates in the list. Click Preview.
• To delete a point so that you can define a new one, highlight the coordinates in the list. Click Delete.
• To add another visit point, return to Step 5.
9. Click Next.
10. In the Network Topology Analysis - Direction and Resistance dialog box, select limits to put on the analysis. For direction and resistance, enter a constant or an expression that references an object data field or linked external database column. The expression will be evaluated for each link. Click (Expression Evaluator) to select data from a list.
• Link Direction — Specifies a direction for the trace. If the box is blank, bi-directional (0) is used.
• Reverse — Uses the reverse of the direction indicated in the Link Direction box.
• Link Direct Resistance — Specifies the resistance to travel in the direction that a link was created. If the box is blank, the length of the line (.LENGTH) is used.
• Link Reverse Resistance — Specifies the resistance in the opposite direction along a link. If the box is blank, the length of the line (.LENGTH) is used.
• Node Resistance — Specifies the resistance to cross the node (for example, resistance for a valve in a pipe network or a junction in a road network). If the box is blank, zero (0) is used.
• Maximum Resistance and Minimum Resistance — Any path that has a total resistance below the minimum or above the maximum is ignored.

For example, if you stored the average speed limit for a link (in miles per hour) in an object data table called street_data, you could find the fastest route between two points by entering the expression (/ .length (* :speed@street_data 5280) which divides the length of each link by the average speed per foot (where 5280 is the number of feet in a mile).

NoteThe best route cannot be calculated if the network topology contains negative resistance values or if all resistance values equal "0" (or use expressions that evaluate to zero). In layman's terms, if all resistance values are all zero, every possible route is as good as any other route, and there is no "best" route to travel.
11. Click Next.
12. In the Network Topology Analysis - Output dialog box, indicate whether or not to view the results of the trace onscreen and whether to save the trace results as a new topology.
• To view the best route analysis onscreen, select Highlight and choose a highlight color.

Use a highlight color that is different from the color of the objects in your map.

• To save the results of the best route analysis as a new topology, select Create Topology and enter a name and description for the new topology.

AutoCAD Map 3D adds topology information, stored as object data, on each element that makes up the best route topology.

13. Click Finish to perform the best route analysis.

To display the order in which to visit points, use annotation to label the best route with the object data stored on the best route topology objects. For more information, see To insert annotation.