Re: a question on ContourPlot

*To*: mathgroup at smc.vnet.net*Subject*: [mg4533] Re: [mg4441] a question on ContourPlot*From*: Allan Hayes <hay at haystack.demon.co.uk>*Date*: Wed, 7 Aug 1996 04:17:40 -0400*Sender*: owner-wri-mathgroup at wolfram.com

"David E. Burmaster" <deb at alceon.com> >Subject: [mg4441] a question on ContourPlot writes > I have made a complicated contour plot (on linear axes) that I > would like to convert to semi-log axes.... > This does NOT work: > Show[ plot/.{a_, b_} -> {a, Log[b]}] > That command converts the y-axis but does not transform the > contours..... > Could anyone pls suggest another approach? David, With cp = ContourPlot[x^2 -y^2, {x,.001,2}, {y,.001,2.72}] cp contains only a matrix of heights from which the polygons and lines are constructed. It also has the option MeshRange -> {{0.001, 2.}, {0.001, 2.72}}. The only effect of cp/{a_, b_} -> {a, Log[b]} on cp is to change this option to MeshRange -> {{0.001, 2.}, {-6.90776, 1.00063}} which, in the display, merely changes the y-axis ticks, as you found. However if you generate the contour lines and polygons (used for shading) explicitely gcp = Graphics[cp] Then lgcp = gcp/{a_?NumberQ, b_} -> {a, Log[b]} will alter these elements as you want. Show[lgcp] (You can see the internal form of cp... by using InputForm[cp] ...) Allan Hayes hay at haystack.demon.co.uk ==== [MESSAGE SEPARATOR] ====