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New Contributor
Posts: 3
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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Technical Evangelist
Posts: 260
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

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New Contributor
Posts: 3
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

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Technical Evangelist
Posts: 260
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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New Contributor
Posts: 4
Registered: ‎11-12-2019

Re: Distortion of the buildings after rectifying the orthophoto,

Yasemin,

May I know why the buildings in orthophoto will be distorted in this way, it lost the original shape of the building's terrace. this orthoimage is generated by the DEM made in eATE.

1.JPG1.JPG

Thank you so much!!!!

Highlighted
New Contributor
Posts: 3
Registered: ‎01-23-2017

Re: Distortion of the buildings after rectifying the orthophoto,

Hi,

 

I used this approach and it works fine with me, I drw the building as afeature layer then I exported the dem as 3d shape layer and remove all the points that intersect with the buildings, then use this layer in extraction the orthophoto.

 

Best

Majdoleen