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Author Topic: Two questions - Number of Markers and Alignment  (Read 1695 times)

Decks

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Two questions - Number of Markers and Alignment
« on: December 17, 2017, 09:38:52 PM »
I have two questions regarding a large project.

I will make about 11 pieces of 600 32-megapixel photos.

1- By manual, I must have 10 accurate markers. Do I need 10 in the whole project or 10 per chunk?

2 - What is the best way to generate the final orthophoto (I am going to do from the DEM), what kind of alignment (for chunks) should I use or how should I do it? (is there any tutorial with this?)

Sorry my english :D

selimerguden

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Re: Two questions - Number of Markers and Alignment
« Reply #1 on: December 21, 2017, 07:49:36 PM »
Hey Andreg,

If you are going to have 11 chunks, they need to be treated as separate projects so I would do 10 markers/ GCP's for each chunk. (You could probably get away with 6-7 per chunk). I am not sure about the orthophoto since I have never exported an orthophoto before however for the orthomosaics I would use High Alignment (preferably), if not Medium  Alignment.  Moreover you can either generate them using the DEM, Mesh, Sparse Cloud or a Dense Cloud. I would use the DEM as my first option. However the advantage of using Mesh over DEM is that sometimes DEM is not generated accurately and if you are creating your orthophoto or  your orthomosaic based on Mesh, your orthomosaic wouldn't be affected even if your DEM is not accurate.

ljurjevic

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Re: Two questions - Number of Markers and Alignment
« Reply #2 on: December 22, 2017, 12:34:15 PM »
I dont want to open new thread for this question, but I really want to hear the answer!

Agisoft is doing the adjustment step with which kind of coordinates? WGS84 cartesian or reference pane coordinate system.
In theory it is correct to use 3D cartesian system and since every defintion of system has TOWGS parameters, I guess it works with  WGS84 cartesian?

Thanks for the reply

selimerguden

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Re: Two questions - Number of Markers and Alignment
« Reply #3 on: December 22, 2017, 04:46:17 PM »
Hey ljurjevic,

You can set your coordinate system to whichever one you want, I believe as default it is doing WGS84 .