Re: Where does the 'z' come from?
- To: mathgroup at smc.vnet.net
- Subject: [mg105431] Re: Where does the 'z' come from?
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Wed, 2 Dec 2009 06:27:03 -0500 (EST)
On 12/1/09 at 4:15 AM, lawrenceteo at yahoo.com (Lawrence Teo) wrote:
>Mathematica v7.0 has this sample for ContourPlot[]
>ListContourPlot[
>Table[Sin[x] Sin[y], {x, -3, 3, 0.1}, {y, -3, 3, 0.1}],
>ContourLabels -> Function[{x, y, z}, Text[Framed[z], {x, y},
>Background -> White]]]
>Where does the z come from? Can I say that the x and y come from the
>iteration by Table[]? Is z an implicit variable?
When an array is plotted by ListContourPlot, z will be the
values in the array itself. After creating the plot notice the
values along the bottom and left edges of the frame. These are
the x,y coordinates for each of the z values. Notice, they range
from 1 to 61 in this plot not -3 to 3 as used in the Table
command that creates the array. That is ListContourPlot has no
knowledge of x and y when given a 2D array to plot. The x,y
coordinates are simply the row,column numbers for each z value
plotted (each array value).