How to visualize the uncertainty of approximated surface away from exact data points?

Is there a way in LF Works to visualize the uncertainty of contact surfaces away from data points using for example colour grading and doing this without touching or editing the interpolant functions?


  • RebeccaInnes
    RebeccaInnes Posts: 9 mod
    Hi JuhaKorpi, 

    Uncertainty isn't something that we specifically categorise in Leapfrog, however I can give you a little workflow that will allow you to evaluate the distance that your contact points are away from the generated surface.  Technically, this does mean creating an 'interpolant function', but it is a very simple step, so I hope that is ok!

    1. Generate the contact points
    Unfortunately, this functionality is not available for contact points created within the surface, so you will need to generate these points again in the Points folder. If this is an on-going need that you have you might want to consider creating the points in the Points folder first and then creating a New Deposit/Erosion/Intrusion > From Points and choosing your created contact points.  This will give the same result as your New Deposit > From Base Lithology, but will allow us to have more access to those input points :smile:

    So, in the Points folder we want to create New Contact Points.  Choose the same points settings as you had used to create your surface.  You can open both dialogs at the same time to make sure everything is the same.

    2. Create a New Distance Function
    Now we have our points, we want to create a distance function for them.  This is why we needed to make the contact points, as you will see that none of your points within surfaces appear in the list of available objects.

    In the Numeric Models folder, create a New Distance Function.

    Press the Selected Objects button and drag your create Contact Points into the Selected objects column.
    Press OK to create the distance function.

    3. Evaluate your distance function on your surface
    Right-click on your surface and choose Evaluations.
    Drag your Distance Function over to the Selected column.  Press OK. 

    4. Visualise the distance of your points to the generated surface
    Drag the Distance Function Evaluation into the scene to visualise your surface with the distance colouring applied.
    You can also add the Legend to get a sense of the distance values.

    5. View and Edit the colourmap of distance values to highlight/categorise uncertainty in the surface generation (optional)
    Click on the Colouring drop-down for the distance evaluation and choose to create a New Colourmap > Discrete.
    Now we will need to change the values plotted in the Histogram.
    Choose Options > Change plotted values > Local values.
    This will change your histogram to only show the values of your evaluation on the mesh.

    Now we have this histogram, we can categorise it based on different distance thresholds to dictate uncertainty in the surface, for example:

    Hope this helps! Happy to answer any questions.
    - Bec