Back to Terrain Module

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Surface Display

Updated November 07, 2023

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Surface displays of the TIN model may be an important aid to design. Features such as Slope Vectors, Shading and 3D visualization can all simplify the design process.

Plan Displays

1. File |Open <Terrain>\Attributes\theme17_sw.terx

2. Home | Insert File. <Terrain>\DTM\Surface Display.terx. Press Open, Choose the default conversion as shown in the figure below. Press OK.

Figure 1: Import Options Dialog Box - Projection Tab

3. Terrain Modeling | Generate TIN to activate the Terrain Calculation dialog box. Turn off all options except Include All as shown in the figure below. Press OK.

Figure 2: Terrain Calculation Dialog Box

Slope Vectors

4. Plan | Plan Options button|Surface tab.

5. Check Slope Vectors box as in the figure below and press the sign beside Slope Vectors which will open the TIN Slope Vector Options dialog box.

Figure 3: Plan windows options dialog box – Surface tab

6. In the TIN Slope Vector dialog box:

   • Turn off Fixed size.

   • Turn on Auto size.

   • Change Maximum length (mm) to 50.

   • Turn on Display at grid locations

   • Type in a Spacing for both X and Y of 200 as shown in the figure below.

7. Press OK twice.

Figure 4: TIN Slope Vector Options Dialog

8. Zoom in on any location to view the directional arrows close up. Notice all these arrows point in the down slope direction and the length of the arrows is directly proportional to the slope. The steeper the slope the longer the arrow as shown in the figure below.

Figure 5: Slope Directional Arrows

Shading

9. Plan |Plan Options | Surface Tab. Turn off Slope and turn on Shading. Press the plus button beside Shading. Select Slope and Degrees as the shading type.

10. Press the Autogen button and set the parameters as shown in the figure below. Press OK.

Figure 6: Autogenerate Shading Intervals Dialog Box

Notice that there are 10 Shading ranges created. In this example only Slope is used. Try some of the other shading attributes to see what they do. They will not be explained in this example.

Figure 7: Tin Shading Options Dialog

11. The TIN Shading Options should match those in the figure above. Press OK.

Notice the slope coloration. The steeper the slope the darker the color. The flatter the area the lighter the color (see Figure 7‑35 below).

Note: Number of shading intervals: In this example, there are 10 shading intervals between yellow and black. The greater the shading intervals the smoother the transition from one color to the next.

Number of legend intervals: If this map is printed in a multi-plot window and a legend is created, the legend would show a color with an interval of slope breaking the total slope into 10 equal intervals. Min/Max shading ranges: If Auto is checked min and max slopes will be determined from the maximum and minimum slopes in the file. If unchecked a limit to the shading slope range can be entered. All other slopes that are outside of the range will remain white.

Figure 8: Shaded TIN Model

3D Displays

Another method of visualizing the TIN is with a 3D Window.

12. Plan | Plan Options button. Turn off Shading found in the Surface tab. Press OK.

13. Open the 3D Window. Select the window using the Navigation part of the bottom Status bar.

14. 3D | 3D Options. Change your 3D Options to match those shown in the figure below. There are two tabs (controlled at the bottom of the dialog), Content and View. Press OK.

Figure 9: 3D Options Dialog - View Tab

Figure 10: 3D Options Dialog - Contents Tab

Note: Show Extents: Shows the entire View

Camera Position – Use Coordinates: Allows entry of the coordinates at which the camera will be placed and the Perspective Angle. The Perspective Angle is the view angle. The larger the angle the larger the view. If Use Current Point is checked the coordinates will be grayed out and the current point in the plan window will be used.

Camera Position - Implicit from Angles, Distance: Allows entry of the
Azimuth, Inclination, and Distance to the target (which is a set ofcoordinates or the current point) entered in by the user in the Target Position area. If Use Forward leg for Azim. is checked then the camera will always face the direction of travel.

Light (sun) Position: The direction and angle of sun in the sky.

Figure 11: 3D View from GIS Contour Data

Zooming and Panning allow you to navigate the 3D image. The Zoom Tools toolbar allows you to zoom or pan once after selecting a function. If you have a mouse with a middle button and a roller you can zoom and pan at any time.

15. View | Pan, or select from the bottom status bar, move your cursor over the 3D window. Click and drag with the left mouse button.

Note: The view moves with your mouse. When you release the mouse the cursor changes back into its previous shape; you must click the Pan button again to initiate a second pan.

16. If you have a middle mouse (even if it is a roller), move your cursor over the 3D window, depress and hold the middle mouse button and note that the cursor changes to the Pan hand. Continue holding the middle mouse and drag to perform a Pan operation

17. Left-click (and hold) in the 3D window, you can now rotate and adjust the position of the 3D window.

18. File | New.