Applies To
	Product(s):	Bentley InRoads Suite
	Version(s):	08.11.07.615
	Environment:	N/A
	Area:	Surface
	Subarea:
	Original Author:	Chris Key, Bentley Technical Support Group

 

Question:

How can I create a DTM in InRoads from a Google Earth Terrain?

Answer:

1. Load Google Earth and zoom to the terrain view you wish to use as an InRoads DTM.
2. Load Microstation and InRoads V8i.
3. Set the Coordinate System of the design file (Tools > Geographic > 1 Select Geographic Coordinate System)
4. Capture the Image (Tools > Geographic > 4 Capture Google Earth Image - datapoint)
5. Follow Google Earth View (Tools > Geographic > 7 Follow Google Earth View)
6. This displays a wireframe of the terrain, to get an image we need to change the display to a smooth style. (Settings > View Attributes > Display Style = Smooth)
7. To get the image in color, you need to go back to Google Earth and Save the Image (it can be saved to the same name).  Then save the settings of the Design File (File > Save Settings), close the DGN and re-open it.  The image should now be in color.
8. Set the view back to a Wireframe display (Settings > View Attributes > Display Style = Wireframe)
9. InRoads V8i has the ability to import the wireframe as a surface from graphics. (InRoads - File > Import > Surface)  One thing to note is Google Earth being a free product, limits the information you can bring from the terrain, therefore you will only get 121 points which isn’t very precise if working with a larger site.  NOTE: This can be done multiple times in different areas, imported into the same surface to get a DTM that is a little more precise.
10. You can now display InRoads DTM Triangles, contours and surface properties to the elevations were pulled from the image.

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