Hi everyone,

 

I'm sorry if this question has already been asked but I couldn't find it and I'm a total beginner with eCognition..

So basically, I have an orthomosaic and a dsm from which I would like to identify boulders out of an area with some vegetation (there's no building nor roads on my site).

I did explore a little bit the ellipse feature view but didn't manage to make it work. Now i'm wondering if I should create a shapefile in ArcGIS (or QGIS) and use it as a reference so as to identify my boulders or if there's any algorithm or function in eCognition that does it automatically? Also it would be interesting for me to compare both if any is possible :) 

I know it might be a really basic question but it would really help me as I'm blocked at this step and need to go on!

Thanks a lot in advance

4 comments

  • Keith Peterson

    Hi Sandra - there are no bad questions, only bad answers! It sounds like you have a good input data position - images and elevation data.
    The next step is to start thinking about how you can uniquely describe the boulders? What characteristics do they have that other features in the image do not have? Then you can user the tools in eCognition to translate your visual understanding of a boulder to one that the computer will understand (the challenge).
    I would start with exploring various segmentations to create the image objects - I suggest looking at multiresoultion segmentation and watershed segmentation.
    Then think about a hierarchal classification approach - use this to start filtering out objects, i.e. classify vegetation, gravel, water etc. so you are left with "potential" boulders.
    Then start refining the potential boulder objects to ideally get one object per boulder. This will allow you to then start discriminating between boulders the other rock material based on features like size, shape etc.

    Check out our eCognition Deconstructed video series on eCognition tv for some helpful explanations of various object refinement algorithms!

  • Christian Weise

    Hello Sandra, in addition to Keith’s suggestions: The DSM layer could make your analysis more robust (What is a boulder object? An elevated object ...). Please investigate this example project. You will find there an approach to estimate the terrain which you can later use to calculate a NDSM so that you can implement height information into your analysis rules.

  • Sanda Gorsic

    Thanks a lot Keith and Christian, helps a lot! Going to try this right now :)

  • Paradis

    Dronegenuity is a leading nationwide provider of aerial drone photography, video production, and mapping services. We operate across a wide range of industries including real estate & development, construction & engineering, energy, financial services, and work with thousands of skilled pilots in North America. https://vd.kinogo.fr/watch/orthomosaic/

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