Contour level at arbitrary (x,y)
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With a contour plot I can use the Data Cursor to click on an (x,y) point and get the Level at that point.
Can I get these Levels from the command line, given an arbitrary (x,y)? I know I can regrid or interpolate the zdata set, but I'd like to extract the values that are plotted, not interpolated values.
Thanks!
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Walter Roberson
on 11 Jun 2013
Set distinct colors for each level. Display. Frame capture. Determine mapping between x/y coordinates and pixels. Now, for each (x,y) pair to be query, map into the captured frame, extract the color, and do a reverse lookup based on the color to determine which contour level corresponds to that color.
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Walter Roberson
on 12 Jun 2013
The polygons generated by contouring are not clean polygons surrounding each contour level. Instead, each edge is drawn just once as part of some polygon. Mostly the uppermost (smallest) contour gets done as a single polygon, but mostly anything else ends out not being explicitly constructed.
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