From dab424bfec3e9171bf2bab10a1b19da7d15aadab Mon Sep 17 00:00:00 2001
From: Giorgio Calderone <giorgio.calderone@gmail.com>
Date: Tue, 28 Apr 2020 18:42:58 +0200
Subject: [PATCH] Updated

---
 docs/src/advanced.md | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/docs/src/advanced.md b/docs/src/advanced.md
index 5a1193a..88d31d0 100644
--- a/docs/src/advanced.md
+++ b/docs/src/advanced.md
@@ -255,6 +255,23 @@ saveas("advanced014e") # hide
 ![](assets/advanced014e.png)
 
 
+The [`contourlines()`](@ref) function also allows to calculate the contour lines encompassing a given fraction of the total counts of a 2D histogram.  E.g. to plot the contours corresponding to 1, 2, and 3 $\sigma$ of a 2D Gaussian distribution:
+```@example abc
+x = randn(10^5);
+y = randn(10^5);
+h = hist(x, y, nbins1=20, nbins2=20);
+
+# Calculate probability within 0 < r < σ
+p(σ) = round(1 - exp(-(σ^2) / 2), sigdigits=3)
+
+# Draw contour lines at 1, 2 and 3 σ
+clines = contourlines(h, p.(1:3));
+@gp palette(:beach, smooth=true, rev=true) "set grid front" "set size ratio -1" h clines
+saveas("advanced014f") # hide
+```
+![](assets/advanced014f.png)
+
+
 ## Animations
 
 The [Multiplot](@ref) capabilities can also be used to stack plots one above the other in order to create an animation, as in the following example: