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2D Profile Lines

Profile Lines are another way of extracting linear data from a 2D area, only these are extracted longitudinally, like a profile plot. Profile lines are frequently used to request the plot of terrain and computed water surface elevation down the centerline of a channel. Profile lines are also used to plot the time series output. The profile line should be drawn perpendicular to the flow direction left to right looking in the downstream direction for plotting time series data for the flow crossing the line.

In GeoHECRAS, the user can create 2D profile lines on the Map View using the Assign Profile Lines and Draw Profile Lines commands. Both commands have similar functionality but somewhat distinct workflows.

Note that these commands should only be used after a successful HEC-RAS analysis run.

Assign Profile Lines

The Assign Profile Lines command allows the user to define a profile line from previously imported CAD or GIS data.

  1. From the Results ribbon menu, expand the Profile Plots dropdown combo box and select Assign Profile Lines command.
  2. The Assign Profile Lines dialog box will be displayed.
  3. Click the [Pick] button. The Assign Profile Lines dialog box will temporarily disappear and a prompt will be displayed on the status bar directing the user to select the CAD or GIS polylines.
  4. Click on the CAD or GIS polylines in the Map View to select them. Once finished, press the [Enter] key or right-click and select Done from the displayed context menu.
  5. The Assign Profile Lines dialog box will be redisplayed showing the count of selected polylines.
  6. In the Profile Line Specifications section, define the prefix for the names of the profile lines in the Auto-name profile line, prefix input field. Note that the Profile line name option is only available when a single polyline is selected. The user can then define the name of the profile line in the Profile line name input field. Otherwise, the software auto-names the profile lines using the defined prefix.
  7. Alternatively, select the Enforce Profile Line as Breakline (optional) checkbox to enforce the profile line as a breakline.
    Enforcing a profile line as a breakline helps in the quick reorientation of orthogonal cells around the profile line to remove jaggies from a skewed profile line. Note that the model should be re-run after enforcing the profile line as a breakline.
  8. In the Cell spacing along the breakline input field, define the cell spacing value along the breakline. By default, the software uses a value of 20 ft. Alternatively, click the […] browse button to measure the cell spacing from the Map View. If this entry is left blank, then the cell spacing value in the vicinity of the breakline will be used.
  9. In the Relaxed cell spacing in 2D flow area input field, define the relaxed cell spacing value that will represent the cell spacing further away from the breakline. Alternatively, click the […] browse button to measure the cell spacing from the Map View. If this entry is left blank, then the cell spacing value in the vicinity of the breakline will be used.
  10. The values in the Relaxed cell spacing in 2D flow area and Cell spacing along breakline input fields should not be the same due to the risk of introducing cell errors along the breakline. When creating the mesh, the software will automatically and gradually transition the cell size from what is defined for the breakline and the area surrounding the breakline.
  11. Once all options are configured properly, click the [Apply] button. The selected polylines from the Map View will be assigned as 2D profile lines.

Draw Profile Lines

The Draw Profile Lines command allows the user to interactively draw 2D profile lines on the Map View.

  1. From the Results ribbon menu, expand the Profile Plots dropdown combo box and select the Draw Profile Lines command.
  2. The Draw Profile Lines dialog box will be displayed.
  3. Click the [Draw] button. The Draw Profile Lines dialog box will temporarily disappear and a prompt will be displayed on the status bar instructing the user to draw a profile line.
  4. Draw the profile line on the Map View. Press and hold the [Ctrl] key to draw a curvilinear segment. Note that if the Create curvilinear polyline checkbox was checked, holding the [Ctrl] key will allow you to draw linear segments.
  5. Always draw the profile line from left to right looking in the downstream direction. Once finished, press the [Enter] key or right-click and select Done from the displayed context menu.
  6. The Draw Profile Lines dialog box will be redisplayed. The status of the Profile polyline field will change to Drawn.
  7. The software automatically names the drawn profile line in the Profile Line Specification section. Notice that the user can also change the name to whatever is desired from the Profile line name input field.
  8. The Enforce Profile Line as Breakline section of this dialog box is similar to what is provided in the Assign Profile Lines dialog box.
  9. Once all options are configured properly, click the [Apply] button to assign the drawn polyline as a 2D profile line.

Profile Line Plot

The software allows the user to request various types of output such as water surface elevation and terrain profile, velocity profile, and flow depth profile along the 2D profile lines.

From the Results ribbon menu, expand the Profile Plots dropdown combo box and select the Profile Line Plot command.
The Profile Line Plot dialog box will be displayed. Alternatively, the user can double-click on the profile line in the Map View to display this dialog box and view output results underneath that profile line.

Notice that while viewing the water surface elevation profile, the terrain profile is included in the plot for reference.

The Scenarios dropdown combo box allows the user to view output results from different scenarios. To learn more about working with multiple scenarios, refer to this article in our knowledge base.

The Profiles dropdown combo box allows the user to view output results for multiple profiles at the same time. By default, the software selects the Max option.

Using the Profile Lines dropdown combo box, the user can select the profile line to display output results underneath it. The plot can display output results for multiple profile lines at the same time.

The user can request various types of output (Velocity, Flood Depth, Time Series-Flow etc.) along the selected profile line(s) from the Plot type dropdown combo box.

The GeoHECRAS software also allows the user to create professional printouts of profile line plots, save them as image file as well as export them to PDF file. To print or export the results of a profile line plot to a different format, right-click anywhere on the plot and select the Export to PDF, Save as Image or Print option.

Display Properties of Profile Lines

The user can also configure the display properties of profile lines plots and their IDs on the Map View. To learn more about this feature, refer to this article in our knowledge base.

About the Author Chris Maeder

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