In this tutorial, you will learn how to use the Automate Transect feature in VO SWMM to assign cross-sections to conduits using a DEM file and a cross-section layer. Follow these steps to successfully utilize this powerful tool:


Before you begin, ensure you have the following prerequisites ready:

  • A DEM file.
  • Conduits in your stormwater network.
  • A cross-section layer containing cross-section lines.

Step 1: Download the Example File

Download the example file provided to follow along with this tutorial.

Step 2: Import the DEM File

  1. Launch VO SWMM and open your modeling project.
  2. Under the “GIS Tool” menu, select “Add Layer.”
  3. Locate and add your DEM file to the project.
  4. Right-click on the imported DEM layer and choose “Zoom To Layer” to visualize the DEM file on the map.

Step 3: Import Nodes

  1. Navigate to the “Micro-Drainage” tab.
  2. Select “Import Layer.”
  3. From the drop-down options, choose “Junction.”
  4. Locate and select the file called “nodes” for Input Source.
  5. Click on “Auto-map” and then “Import” to import the nodes. You will now see the nodes displayed on the map.

Step 4: Import Conduits

  1. Still under the “Micro-Drainage” tab, click on “Import Layer” once again.
  2. From the drop-down options, this time, select “Conduit.”
  3. Choose the conduits file from your project.

Step 5: Add the Cross-Section Layer

  1. Under the “GIS Tool” menu, click on “Add Layer.”
  2. Select the cross-section layer from your project files.
  3. Right-click on the cross-section layer and move it up the layer stack to make sure you can see the cross-section lines clearly on the map.

Step 6: Extract Cross-Sections

Now that you have all the necessary layers imported, you’re ready to extract cross-sections.

  1. Locate and click on “Automate Transect” under the “Micro-Drainage” tab.
  2. In the Automate Transect tool dialog, assign the DEM file to the appropriate field.
  3. Assign the cross-section layer to the corresponding field.
  4. Press the “Start” button to initiate the cross-section extraction process.

Step 7: Verify and Save

  • VO SWMM will automatically extract transects from the DEM file and assign them to the conduits.
  • After completion, review the results to ensure the cross-sections have been assigned accurately. Make any necessary adjustments if needed.
  • Save your project to retain the changes made by the Automate Transect feature.