3Dsurvey

3Dsurvey => General Discussion => Topic started by: katrina.heinrich on March 17, 2022, 11:26:18 AM

Title: How to generate an accurate orthophoto of a bridge?
Post by: katrina.heinrich on March 17, 2022, 11:26:18 AM

I'm trying to calculate an orthophoto of a bridge, but it doesn't come out well even after recalculating it.

Title: Re: How to generate an accurate orthophoto of a bridge?
Post by: ivan.zan.barbaric on March 17, 2022, 01:59:50 PM

Yes, Bridges are tricky.  In this case, I recommend adding bridge points manually to terrain points by selecting them using the select tool.

First delete the points below the terrain, (you can try using Top-down and Ortho-mode) and select the bridge Next go back to perspective mode and deselect the bridge. You will end up with a selection of points directly below the bridge, like in my screenshot. Delete these points!
(https://forum.3dsurvey.si/index.php?action=dlattach;topic=71.0;attach=153)
Select the bridge points again, right-click the Ground Class and select "Set this class to selected points" from the context menu.
(https://forum.3dsurvey.si/index.php?action=dlattach;topic=71.0;attach=155)
At last, create the orthophoto out of this DTM model.
(https://forum.3dsurvey.si/index.php?action=dlattach;topic=71.0;attach=157)
You should get this kind of result:
(https://forum.3dsurvey.si/index.php?action=dlattach;topic=71.0;attach=159)
Alternatively, you can make a textured 3D Model and true-orthophoto instead of this workflow.