Georeferencing a HEC-RAS Model to a Map Location

When importing a HEC-RAS model, the imported model will be assigned to a local coordinate reference system. If the project has been assigned a coordinate reference system, then the HEC-RAS model can be georeferenced with the other data within the project. In that way, the HEC-RAS model and will lie in its correct location on the Map View.

Manually Georeferencing a HEC-RAS Model

If the imported HEC-RAS model has not been defined using projected coordinates, these steps can be followed to georeference the HEC-RAS model to a map:

  1. If the Map View still shows the imported HEC-RAS model, see this article to restore the Map View CRS.
  2. Zoom to the location on the Map View where the HEC-RAS model should be placed.
  3. From the Map Data Layers panel, click on the HEC-RAS layer and drag it on top of the Map View. As the HEC-RAS model is dragged over the map, an outline of the HEC-RAS model limits will be shown to the user.
  4. Releasing the mouse button will cause the HEC-RAS model to be placed at the selected location.

The HEC-RAS model location on the Map View may need to be further adjusted to correctly align it with other map features. Follow these steps to refine the georeferencing:

  1. Click on one of the elements of the HEC-RAS model. The element will highlight to show that it is selected.
  2. Press [Ctrl+A] on the keyboard. This will cause all of the HEC-RAS elements to become selected.
  3. Press function key [F2] on the keyboard. A bounding box will be shown around the selected HEC-RAS model. This bounding box allows the user to move, scale, stretch, and rotate the selected HEC-RAS model.
  4. Click and drag on the interior of the bounding box to move the HEC-RAS model around on the Map View.
  5. Hover the cursor over the displayed rotation handle (i.e., circle) displayed above the bounding box. A rotation anchor point will be displayed at the center of the bounding box. The rotation anchor point can be repositioned anywhere on the interior of the bounding box. Clicking and moving the rotation handle will cause the HEC-RAS model to rotate around the rotation anchor point.
  6. Click and drag one of the corners of the bounding box to scale up and down the size of the HEC-RAS model uniformly. Holding down the Shift key will cause the HEC-RAS model to scale up and down in size non-uniformly. Holding down the Alt key will cause the HEC-RAS model to scale up and down in size uniformly, relative to the center of the bounding box.
  7. Click and drag one of the sides of the bounding box to stretch or shrink the HEC-RAS model in that direction. Holding down the Shift key will cause the HEC-RAS model to scale up and down in size uniformly. Holding down the Alt key will cause the HEC-RAS model to stretch in that direction, relative to the center of the bounding box.

Note that if a mistake is made during the fine tuning of the move, scale, stretch, and rotate georeferencing of the HEC-RAS model, the Undo command can be used to back up to a previous georeferenced state.

Georeferencing a HEC-RAS Model by CRS Assignment

If the imported HEC-RAS model has been defined using projected coordinates, these steps can be followed to georeference the HEC-RAS model to a map by assigning a coordinate reference system:

  1. If the Map View still shows the imported HEC-RAS model, see this article to restore the Map View CRS.
  2. Confirm that the correct project CRS is being used by looking in the lower right corner of the application and examining the CRS that is listed.
  3. Click on the […] properties button for the HEC-RAS layer within the Map Data Layers panel.
  4. The HEC-RAS Properties dialog box will be displayed.
  5. Click on the Spatial Reference tab contained within the Properties dialog box.
  6. Click on the [Assign Current CRS] button. This will cause the HEC-RAS layer to be assigned to the Map View CRS. The HEC-RAS model should be visible on the Map View along with the other data.
  7. Click on the [OK] button in the displayed Properties dialog box finish the process.

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