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New Contributor
Posts: 2
Registered: ‎01-23-2017
Accepted Solution

Distortion of the buildings after rectifying the orthophoto,

Distortion of the buildings after rectifying the orthophoto,

 

I couldn’t figure out why there is a distortion in the rectified orthophotos taking into consideration that I used the Dem which is derived by Erdas. The row images are fine and with overlap (60%).

 

The number of GCPs is 6, and the Auto derived Tie Points are 600.

 

What might be the issue here?

Clip_229.jpg

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Staff
Posts: 209
Registered: ‎10-21-2015

Re: Distortion of the buildings after rectifying the orthophoto,

Hello,

 

It is advisable to review terrain extraction results over stereo imagery with Terrain Editor before generating orthos. Because the automated DTM extraction processes correlates top of trees, buildings, and other extruding features on the earth’s surface as well. You may see these kinds of effects, disfiguration of straight lines, around buildings, bridges and other features on orthos. In these instances, you have to edit the initial mass points and reshape them so that they fit, reflect, and represent the earth’s surface. You may use Terrain Editor to edit the points around the buildings.

 

Best Regards,

Yasemin

New Contributor
Posts: 2
Registered: ‎01-23-2017

Re: Distortion of the buildings after rectifying the orthophoto,

Thank you YaseminS,

 

I went through your suggestion and it works fine with me, but I have one question, Do I need to edit all the DEM points for all the building, trees, ...? this will take much of time from me. May you please guid me to use the best practical to edit the Dem from your experince to minize the time and the effort.

 

Thank you in advance.

 

Best

Majdoleen

Staff
Posts: 209
Registered: ‎10-21-2015

Re: Distortion of the buildings after rectifying the orthophoto,

Hello,

 

Please check the quality of the DEM on stereo imagery in TE and edit the problematic areas only. You may refer to Terrain Editor documentation at below link for quick editing tips and tips for different editing operators:

https://hexagongeospatial.fluidtopics.net/reader/~P7L4c0T_d3papuwS98oGQ/UVuhGLTZhdbS4iAMzCvCBw

 

Best Regards,

Yasemin

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