shade under curves

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Hello,

I have made a plot of 3 different curves and Im trying to shade the area under the curves where the horizontal line intersect the other 2 curves. It should be shaded so that if it's under the larger curve, it has a different pattern than the smaller curve. I have an example of what it should look like in the attached jpeg file. I have read the manual but couldnt figure out how to do this so any help would be greatly appreciated.

Thank you.
Your question is similar to that raised in Igor Exchange Node 4650. You seem to be able to find the intersection points you need, so I would opt for 741's suggestion there: construct a 2-point wave at the intersections you want, add it to the graph, shade its display and order its sequence behind the other waves.

May 7, 2013 at 09:38 am - Permalink

Here is a generalization that can use a non-flat boundary wave, and does not require explicit location of the wave intersections. I simulated your data with waves I called wBig, wSmall, and wBound. Then I used the following function
function shade()
    WAVE wBig, wSmall, wBound
    duplicate/O wBound, shadeBig, shadeSmall
    shadeBig    =  wBound*(wBound<=wBig)
    shadeSmall  = wBound*(wBound<=wSmall)
end

Note the use of logical waves to define the shade regions. The waves shadeBig and shadeSmall were appended to the graph, and Fill To Zero mode was selected for each. Finally the Reorder Traces... was selected from the Graph menu to give the displayed result.
Shading.png (50.81 KB)

May 8, 2013 at 09:59 am - Permalink

Thank you, that was very helpful. I was able to make the shade exactly as needed.

May 8, 2013 at 07:46 pm - Permalink