Planar Orthomosaic Generation - Identical view angle selection between projects?

[captcook42]

Hi all,

I have searched the forum but I couldn't seem to find this exact issue. I have multiple drone-based imaging sensor types (e.g., MicaSense multispectral, thermal, optical), each of which I have processed and generated a nadir orientation orthomosaic in a unique Agisoft project.

Because these images are of the side of mountains, I would like to also export oblique planar orthomosaics from a specific orientation / perspective. While I have done this before for individual layers, I have never done this for multiple sensors (again, in unique projects) such that I could regeoreference and overlay (or combine) the different sensor layers into a single multi-band raster. I have found that this process (the regeoreferencing) is nearly impossible to do unless one gets the exact same position and angle between different projects, which is very difficult to do. Especially when one is going off of the angle of the point cloud for thermal imagery (which is just a grayscale point cloud and very hard to determine such an exact position and orientation).

I want to know if there is some way to choose a precise look angle / location to export an oblique planar orthomosaic (and DEM), such that I could repeat or reuse the exact same position and angle between different projects.

Thank you for your time. Please let me know if you need any additional information or have any questions from me.

Thank you,
Capt. Cook

[Paulo]

Hi capt,

I think this could be done by scripting. In example, I am showing 2 chunks, one rgb and another thermal. Supposing that both chunks have been georeferenced and  that they use same surface  (in this case model from high resolution rgb) than a planar oblique looking ortho can be generated using same view and position for both chunks....

Send me a PM for more details...

[captcook42]

Hi Paulo,

Thanks for your response. Unfortunately, I already have dozens of Agisoft projects where I am analyzing a single sensor type (separate projects for thermal, multispectral, optical, etc.) for numerous different sites. As these are done in each their own project, they are each using their own point clouds (or DEMs) as their own unique surface for the orthomosaic generation.

Your processing sounds to me as though it has numerous benefits for co-aligning datasets, especially for a mix of high-res optical and lower res (e.g., thermal, mutlispectral) datasets. I may attempt that going forward.

I was wondering if there might be some way I could make reference points that define a look angle, position, and direction, and then copy those reference points between Agisoft projects to define the view geometry, but I have not been able to find how to do so.

Thanks,
Capt. Cook

[Alexey Pasumansky]

Hello Capt. Cook,

If all the projects are georeferenced in the same coordinate system, then you can create 3-4 markers in the first project, input XYZ coordinates for them to the Reference pane and check on the markers in the pane. Then build orthomosaic using Planar projection option defined by those markers. Then just save same markers to CSV/TXT file  - just labels with coordinates in each line, import to the next project and use the same plane definition by same markers.

[captcook42]

Hi Alexey,

Thanks for your response. I'll give this a try and let you know how it goes!

-Capt. Cook