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Hi NCL-Talk,
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<div class="">I am attempting to overlay contours of standardized Geopotential height over changes in standardized Geopotential height. All I want to have in the overlay is a zone of positive and a zone of negative values. But I am having trouble understand
how this is working. Especially since the contour intervals do not make sense (in the example below).</div>
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<div class="">Cheers,</div>
<div class="">-Jonathan</div>
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<div class="">Code snippets.</div>
<div class="">; generate positive and negative zone</div>
<div class="">PI_Z_rmMean_contrained = PI_Z_rmMean<br class="">
PI_Z_rmMean_contrained = where(PI_Z_rmMean.ge.80..or.PI_Z_rmMean.lt.-80.,PI_Z_rmMean,PI_Z_rmMean@_FillValue)<br class="">
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res1@cnLevelSelectionMode = "ExplicitLevels" <br class="">
res1@cnLevels = (/-160.,-80.,80.,160./) ; Diffs<br class="">
res1@gsnContourNegLineDashPattern = 1 ; sets negative contours to dash pattern 1<br class="">
res1@cnLineThicknessF = 1.<br class="">
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<div class=""> plotPI = gsn_csm_contour(wks,PI_Z_rmMean(0,0,:,:),res1)<br class="">
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<div class=""> plotLGMvsPI = gsn_csm_contour_map(wks,LGM100_vs_PI(0,0,:,:),res)</div>
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<div class=""> overlay(plotLGMvsPI,plotPI)</div>
<div class=""> plotTemp(0) = plotLGMvsPI</div>
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