Possible way to get a footprint of a crop of an image?

[srathore]

I'm slightly new to using Metashape but some of my research requires me to essentially look at a crop of an image taken by a drone camera (center crop), I know its possible to get the footprint of a camera from the list and there was a n old script for that in the forums. But is it possible to make a script to export/ get the footprint of a 2000x2000 crop of a 8192x5460 image taken by a DJI drone camera?

[Paulo]

Hello srathore,

from the github script https://github.com/agisoft-llc/metashape-scripts/blob/master/src/footprints_to_shapes.py#L50, you would need to edit the following that takes the four pixel corner coordinates  of an image:

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        for (x, y) in [[0, 0], [sensor.width - 1, 0], [sensor.width - 1, sensor.height - 1], [0, sensor.height - 1]]:to something like:

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        for (x, y) in [[2000, 2000], [4000, 2000], [4000, 4000], [2000,4000]]:to reflect a 2000 by 2000 image crop from position u=2000 pix and v=2000 pix....

PS. to get a crop centered, I guess you would need to define the 4 point list as:

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[[hw-1000, hh-1000], [hw+1000, hh-1000], [hw+1000, hh+1000], [hw-1000, hh+1000]]
where:
        hw = camera.sensor.width/2
        hh = camera.sensor.height/2
Hope this can help,

[srathore]

That, looks like it worked, thanks a lot. Is there a way I could export these values?

[Paulo]

Hi again,

if you mean exporting the polygons created by the footprints2shapes script, you can look at chunk.exportShapes method . From API reference manual, p.39:

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exportShapes(path='', save_points=False, save_polylines=False, save_polygons=False[, groups ],
format=ShapesFormatNone[, crs ][, shift ], polygons_as_polylines=False, save_labels=True,
save_attributes=True[, progress ])

[ankit108]

Hello Paulo,
I have a similar question. What work around should I do to get the footprint of an Orthomosaic like we got footprint for each camera in the question mentioned above?
By footprint of ortho, I meant that a shape that follows boundary of an Ortho.

[Paulo]

Hello ankit,

one workaround would be to generate seamlines from Orthomosaic context menu (right click on ortho in Workspace). This will create a shapes layer with seamlines as multi polygons. See attachment... You could then export this layer and in a Gis software combine all the seamlines multi polygons into one polygon representing the ortho footprint.....