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Messages - ChrisC

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Anyone have any ideas about this?

Alexey, do you have any suggestions about this? Thanks!

Hi Alexey, thanks for responding.

Yes, I am using the same resolution. I Build the DEM from the mesh using the default resolution (0.00135878 m)
Then I build the orthomosaic, click the Metres... button and enter in the same resolution (0.00135878 m)
The created DEM and Orthomosaic both have same resolution (1.36 mm/pix) and the pixel sizes are exactly the same.

I checked for the shift by zooming all the way in and visually checking for difference on screen, double clicking the mosaic and then double clicking the DEM. Thats where I see the shift, less than a pixel. 

I have an area where I created a DEM and orthomosaic but when I zoom way in on the pixels I see there is a slight shift (less than a pixel). I need to be able to overlay these products so that a pixel in the DEM is completey coincident with an underlying pixel in the orthomosaic. I have tried several different settings but shifting occurs no matter what. I would think they should be spot on considering they generated from the same source.  Is there something I'm missing?

General / photomosaic swirled blurring or distortion
« on: August 21, 2019, 09:14:49 PM »
I have a question about something I see in a lot of the mosaics we have constructed using GoPro Hero photos as source imagery.  When zoomed pretty far in I notice areas where a sort of blurry swirling distortion happens. I have attached a screen shot of an example of this.

Can anyone shed some light why this happens and is there a way to reduce it?

Is it related to clarity of the photos or maybe the orthorectification process?

General / Is External GPU an good way to increase performance?
« on: May 29, 2019, 12:15:02 AM »
I asked my IT department to upgrade the GPU on the computer we use for SfM work. They agreed but want to add an external GPU instead of a better internal graphics card.  So I am wondering:

1. Is external GPU a good way to increase performance?
2. Are there any external GPUs that are known to work well with Metashape?

3. Conversely, are there any external GPUs to stay away from?

General / Re: Converting a model to an Orthomosaic
« on: March 14, 2019, 04:48:45 PM »
Have you tried creating a tiled model and exporting that?  The tiled model is the only thing I have tried that works in ArcGIS (I put it in a global scene). That works pretty well.   I have tried many of the other formats and have run into the same issues you describe.

Thanks for the tip, I will definitely check on the orientation!

Thank you Alexey! 


How have you input height values into your project - do you have Ground Control Points (GCPs)? or are you relying on camera positions?

Hi Dave, sorry I should have gave more info. This is an underwater area of coral reef. We had a diver taking the photos underwater, so we have no coordinates for true GCPs. But we do have several 30cm by 30cm cards the divers placed throughout the plot, so I am able to create pretty accurate scale bars, which I believe is what Agisoft is using to create the DEM.

Thanks for your help! 

General / Digital elevation models - why are there have negative heights?
« on: February 21, 2019, 04:23:33 AM »
Hello, I am a little confused why the DEMs I generate have negative values? See attached example where the height ranges from 1 meter to -4.58 meters. Is it because photoscan picks an arbitray point and then every thing is either above or below that point?  Would it be wrong to add 4.58 to all values?   Thanks for any help on this!

General / Re: Incorrect alignment problem
« on: September 14, 2018, 04:50:30 PM »
Hello Chris,

Such behavior can be related to low overlap between two parts of survey.

You can try to reset the alignment for one of these parts (leaving only correct part of alignment) and then use Align Selected Cameras option for the NA (Not Aligned) cameras.

That worked perfectly. Thanks!

General / Re: ArcGIS integration
« on: September 12, 2018, 09:51:27 PM »
Thanks, I will give the SLPK format a try when I get a chance!

General / Re: Incorrect alignment problem
« on: September 12, 2018, 09:26:59 PM »
Thanks, I will give that a try!

General / Incorrect alignment problem
« on: September 12, 2018, 06:04:44 PM »
Hello, please see the attached screen shot to see what I am trying to describe here. In terms of numbers of photos aligned I got great alignment, but unfortunately part of it is inaccurately aligned.

I am wondering what is causing part of the sparse cloud to get tilted at about a 90 degree angle from the rest of the cloud? This is an underwater seafloor and is very flat, so the whole thing should be flat.  Any ideas on how to fix this? 

The images were captured from an underwater video that was taken back in 2016, so there is no EXIF or any sort of lat/longs.  Unfortunately I could not find out the type of video camera used, but I think it was a GoPro.


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