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Author Topic: How can I know the "Resolution" or "accuracy" of my dense point cloud ?  (Read 1818 times)

Bruno Miguez

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Hi! I have this kind of simple question, but I am not sure about the answer. So I would like to check it ..

When we are working with a 2D raster data, as a DEM or an Orthomosaic, we easily have the information of the resolution of our data.
In Agisoft it is easy to check this information at the workspace.

But what about the resolution of the point cloud I am working on ? How can I know it ?

Can I use the resolution of the DEM generated from my point cloud, to refer to the resolution of my point cloud itself ?

Cheers,

Bruno

archaeo42

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Okay, let's see if I got your question right...

A point cloud will not have a "resolution" the way a raster does simply because all the points will not be a an equal distance from each other. For instance, there can be an area of your model where you have, say, 100 points/square cm, and another where not as many photos were taken where you'll only have 10 points/square cm. Your point cloud density will also greatly vary depending on the parameters you chose for the alignment (no. of photos, tie points, key points, etc) and the dense cloud generation (high density, medium density, etc).
If you want to get an average density of points, you could take the number of points you have an divide it by the surface area of your model.

As for accuracy, that's an entirely different can of worms.


Cheers

JMR

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It is hard to predict and also to know dense cloud density (or average points spacing, if you like) but once it is created it is easy to filter to a desired spacing. So you could be able to subsample yor cloud to a value that is fine for you... yeah, it soulds like climbing to the top of a mountain and then descend to a desired altitude instead of climbing directly to that point, but... I'm sorry, no straight path in this case as far as I know.
best
GEOBIT