The Elevation Profile command is used to display the elevation profile plot, profile line details, and profile line geometry for a selected polyline and terrain surface.
Follow the steps below to use the Elevation Profile command:
- From the Terrain ribbon menu, select the Elevation Profile command.
- Selecting this command splits the Map View into two sections: the top shows the Map View, and the bottom displays the Elevation Profile panel.
- Now, select a polyline from the Map View and the corresponding elevation profile will be displayed in the Elevation Profile panel. Note that only one polyline can be selected at a time.
Station – Elevation Point Tracking
In the Elevation Profile panel, dragging the mouse over the Elevation Profile plot displays a vertical line with a tracker, and the corresponding station and elevation values appear in the plot legend. In addition, a vertical arrowhead is also shown on the Map View that updates dynamically over the mouse drag. The arrowhead displays the same station and elevation readings as displayed in the Elevation Profile plot.
To turn off the active elevation profile tracking from both the Map View and Elevation Profile panel, uncheck the Track surface checkbox option in the top right corner of the panel.
Note that if the user grabs the polyline from the Map View and moves it around the terrain surface, the Elevation Profile panel is dynamically updated to show the new elevation profile.
Elevation Data Source Selection
The Elevation Data panel allows the user to select the elevation data source(s) to be used to extract the elevation profile. By default, this panel will reference the selected terrain surface in the Scenario Manager (if one is defined). If no terrain surface is selected in the Scenario Manager, then this entry will be undefined (i.e., blank). Refer to this article in our knowledge base to learn more about the Scenario Manager dialog box.
In the Elevation Data panel, the user can select the elevation data source from the Extract Elevation Data section. This section is enabled by default and allows the user to select primary and secondary elevation sources.
Note that if the checkbox at the Extract Elevation Data section is unchecked, then the options contained within this section will be disabled (i.e., grayed out).
The Primary Elevation Data and Secondary Elevation Data panels are used to define the primary and secondary (if available in the project) elevation data sources for extracting the elevation profile. Depending on the elevation data source type selected, the content of these panels changes to specify the additional elevation data information.
The software supports the following surface types, each differing in how terrain data are represented and processed:
- CAD Drawing
- Elevation Grid
- GIS Contours
- LandXML Data
- Terrain Surface
- TIN surface
For example, the following table provides a comparison between TIN and DEM in terms of how terrain data are represented and processed:
| TIN (Triangulated Irregular Network) | DEM (Digital Elevation Model) | |
| Data Structure and Representation | Terrain is represented as a network of non-overlapping triangles constructed from irregularly spaced points. Each triangle has precise vertex coordinates and elevation values, allowing for detailed and accurate modeling of complex terrain features. | Terrain is represented as a regular grid of cells (pixels), where each cell has a single elevation value. This provides a uniform, grid-based approximation of the surface. |
| Cross Section Calculation | Cross sections are created by intersecting a polyline (section line) with the triangular facets of the TIN. Elevation values are calculated exactly where the line crosses the triangle edges, resulting in highly accurate profiles. | Cross sections are created by sampling elevation values from the raster cells along the section line. These values are interpolated from surrounding cells, which can introduce some error, particularly in areas with steep or variable terrain. |
| Accuracy and Detail | It is highly accurate, especially in areas with steep slopes or complex terrain features. | It is dependent on grid resolution, higher-resolution DEMs improve detail but increase file size and processing time. |
| Processing Efficiency | It can be more computationally intensive for large datasets due to its irregular structure but allows for precise terrain modeling. | It can be more efficient for large areas due to the uniform structure and simplified processing. |
When a secondary elevation data source is available, the software forms a concave hull around the primary elevation data source to identify its bounds. For locations where elevation data from the primary data source are unavailable, the software will use elevation data from the secondary data source.
Note that the user cannot utilize the same data source to define both the primary and secondary elevation data.
The user can click the [Swap Sources] button to swap the selected elevation source from primary elevation data to secondary elevation data and vice versa.
Extract Options
This section contains the Ignore zero elevation values checkbox option. This checkbox option allows the software to prevent bad (i.e., zero value) elevation points from impacting the plotted profile. By default, this checkbox option is checked.
Profile Line Properties
The Selected Profile Line Details section displays the profile line properties when an elevation data source is defined for the selected polyline.
- Polyline length
This read-only field displays the total length of the selected polyline.
- Maximum elevation
This read-only field displays the maximum elevation along the entire polyline.
- Minimum elevation
This read-only field displays the minimum elevation along the entire polyline.
- Elevation range
This read-only field displays the difference between the maximum and minimum elevations along the polyline.
Note that if the selected polyline does not lay entirely over the defined elevation data source, then only the length property will be displayed and other properties will remain blank and shown as “NA” (i.e., Not Available).
Profile Line Station – Elevation Data Grid
The Profile Line Geometry section contains a data grid that displays the profile line station-elevation data for the selected elevation source. By default, the Elevation source dropdown combo box selects the default elevation source selected in the Scenario Manager dialog box. If the user selects a different elevation source from the dropdown combo box (if available), then its corresponding profile line geometry will be displayed.
The profile line geometry is covered along the length of the selected polyline. The top right corner of the above panel displays the total points into which a selected polyline would have been divided. In addition, the Horizontal Station present at the last point in the Profile Line Geometry grid denotes the length of the selected polyline.
The length of the selected polyline can also be seen in the Data Explorer panel of the software. Refer to this article in our knowledge base for more information about viewing and editing the GIS attribute data using Data Explorer.
Selecting Other Elevation Sources
The Other Sources panel lists all the available elevation source(s) present in the project. In addition, if the user selects multiple elevation sources from the list, the software will then display the corresponding plots in the Elevation Profile panel.