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Author Topic: Coded markers: adjustable page size, custom location for numbering  (Read 1001 times)

nola

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Coded markers: adjustable page size, custom location for numbering
« on: September 06, 2021, 03:39:31 PM »
I am trying to print relatively large (30-35cm) coded markers but when I have a center point radius value of say 50mm, the coded target becomes much larger then the default paper size (A4 i assume). It would be nice to be able to set a custom page size or that Agisoft changes the page size automatically.

The other request would be to allow the numbering of the coded target to have a custom location, especially useful for larger target size. When the font is increased (ex. 90) the number is inside the coded target.

I am trying to follow the guidelines in this post for using coded targets in drone surveys.
https://www.agisoft.com/forum/index.php?topic=2768.msg32898#msg32898

SAV

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Re: Coded markers: adjustable page size, custom location for numbering
« Reply #1 on: September 07, 2021, 10:57:42 AM »
Hi Nola,

There is a simple workaround. Use Adobe Illustrator to open the PDF. It is read as a vector graphic, which means you can then scale it to the size you want without loosing any quality (no need to make them so big in Agisoft Metashape). You can then also adjust the paper size.

I assume it also works with Inkscape which is a free and open source alternative to Adobe Illustrator.

All the best.

Regards,
SAV

nola

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Re: Coded markers: adjustable page size, custom location for numbering
« Reply #2 on: September 07, 2021, 04:35:34 PM »
Thanks for the suggestion!

I ended up adjusting the size so it fills the A4 page and then printing it to A3 by scaling up in the printer settings.

I do wish there could be more than 161 coded targets though.

We are looking to place them out along different administrative boundaries to see if they could be used to minimize GPS work so we want to put out hundreds of targets.

JMR

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Re: Coded markers: adjustable page size, custom location for numbering
« Reply #3 on: October 04, 2021, 08:53:59 AM »
Hi
In my humble opinion, using coded targets for aerial survey is pointless. Targets are very easy to identify without using them, even in case of non referenced images. Can you please tell us why do you think you need them? perhaps we can tell you a simpler approach.

José Martínez
Agisoft Training

nola

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Re: Coded markers: adjustable page size, custom location for numbering
« Reply #4 on: October 04, 2021, 12:32:00 PM »
Our test case is to see if the coded target can help us identify the locations of potentially hundreds of markers. These of course would not be used in the traditional gcp method of correcting the model.

Basically we have to go out and survey castre boundaries that are marked with a small pipe in the ground. Each property has min of 4 pins and we have about 300 properties to survey. An idea was to see if we could place the coded markers on the property pins and use Agisoft to auto detect these.

The question we want to answer is:
If we were to say only survey about 50 % of the pins, could we get the positioning of the remainder with a decent accuracy from the 3d model and locate them with the help of coded targets.


JMR

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Re: Coded markers: adjustable page size, custom location for numbering
« Reply #5 on: October 04, 2021, 08:38:15 PM »
Hi, Nola:
I understand better now. But still I think it can be done with non coded targets and they are cheaper to produce and do not need to be too large to be auto-detected.
Metashape can autodetect circular or chess type targets. You could use any of them and you can mark with paint around a selection of ground marks that are surveyed. The surveyed points should provide a good framework for referencing the job, with even distribution and including some in the inside area.
I guess you wont need to survey but a small fraction of the whole amount of markers. Even with only 10% could be enough although it depends on the actual properties distribution and your flight structure and some factors that would require more insight of your case.
Best
José Martínez
Agisoft training

nola

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Re: Coded markers: adjustable page size, custom location for numbering
« Reply #6 on: October 05, 2021, 01:29:22 AM »
Thanks for the tips and suggestions!
We will test with different types of targets on a smaller area to see which ones will work best with our workflow.

Now if only the weather was better here in Sweden!