Mercurial > hg > octave-nkf
diff doc/interpreter/plot.txi @ 6888:b3d286e8a243
[project @ 2007-09-12 06:40:58 by jwe]
author | jwe |
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date | Wed, 12 Sep 2007 06:44:50 +0000 |
parents | ab11bdb09820 |
children | ebff56d6b0a8 |
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--- a/doc/interpreter/plot.txi +++ b/doc/interpreter/plot.txi @@ -4,85 +4,219 @@ @node Plotting @chapter Plotting +@cindex plotting +@cindex graphics @menu -* Two-Dimensional Plotting:: -* Specialized Two-Dimensional Plots:: +* Plotting Basics:: +* Advanced Plotting:: +@end menu + +@node Plotting Basics +@section Plotting Basics + +Octave makes it easy to create many different types of two- and +three-dimensional plots using a few high-level functions. + +If you need finer control over graphics, see @ref{Advanced Plotting}. + +@menu +* Two-Dimensional Plots:: * Three-Dimensional Plotting:: -* Manipulating Existing Plots:: * Plot Annotations:: * Multiple Plots on One Page:: * Multiple Plot Windows:: -* Printing Plots:: -* Test Plotting Functions:: -* Interaction with gnuplot:: +* Printing Plots:: +* Test Plotting Functions:: @end menu -@node Two-Dimensional Plotting -@section Two-Dimensional Plotting +@node Two-Dimensional Plots +@subsection Two-Dimensional Plots + +The @code{plot} function allows you to create simple x-y plots with +linear axes. For example, -The basic plotting commands are: +@example +@group +x = -10:0.1:10; +plot (x, sin (x)); +@end group +@end example + +@noindent +displays a sine wave shown in @xref{fig:plot}. On most systems, this +command will open a separate plot window to display the graph. -@cindex plotting -@cindex graphics +@float Figure,fig:plot +@image{plot,8cm} +@caption{Simple Two-Dimensional Plot.} +@end float + +The function @code{fplot} also generates two-dimensional plots with +linear axes using a function name and limits for the range of the +x-coordinate instead of the x and y data. For example, -@DOCSTRING(axes) +@example +@group +fplot (@@sin, [-10, 10], 201); +@end group +@end example + +@noindent +produces a plot that is equivalent to the one above, but also includes a +legend displaying the name of the plotted function. @DOCSTRING(plot) -@DOCSTRING(line) - @DOCSTRING(fplot) -@DOCSTRING(drawnow) +The functions @code{semilogx}, @code{semilogy}, and @code{loglog} are +similar to the @code{plot} function, but produce plots in which one or +both of the axes use log scales. + +@DOCSTRING(semilogx) -@DOCSTRING(shg) +@DOCSTRING(semilogy) -@DOCSTRING(hold) +@DOCSTRING(loglog) + +The functions @code{bar}, @code{barh}, @code{stairs}, and @code{stem} +are useful for displaying discrete data. For example, -@DOCSTRING(ishold) +@example +@group +hist (randn (10000, 1), 30); +@end group +@end example -@DOCSTRING(newplot) +@noindent +produces the histogram of 10,000 normally distributed random numbers +shown in @xref{fig:hist}. -@node Specialized Two-Dimensional Plots -@section Specialized Two-Dimensional Plots +@float Figure,fig:hist +@image{hist,8cm} +@caption{Histogram.} +@end float @DOCSTRING(bar) @DOCSTRING(barh) +@DOCSTRING(hist) + +@DOCSTRING(stairs) + +@DOCSTRING(stem) + +The @code{contour} and @code{contourc} functions produce two-dimensional +contour plots from three dimensional data. + @DOCSTRING(contour) @DOCSTRING(contourc) -@DOCSTRING(hist) - -@DOCSTRING(loglog) - -@DOCSTRING(polar) - -@DOCSTRING(patch) +The @code{errorbar}, @code{semilogxerr}, @code{semilogyerr}, and +@code{loglogerr} functions produces plots with error bar markers. For +example, -@DOCSTRING(semilogx) - -@DOCSTRING(semilogy) +@example +x = 0:0.1:10; +y = sin (x); +yp = 0.1 .* randn (size (x)); +ym = -0.1 .* randn (size (x)); +errorbar (x, sin (x), ym, yp); +@end example -@DOCSTRING(stem) +@noindent +produces the figure shown in @xref{fig:errorbar}. -@DOCSTRING(stairs) +@float Figure,fig:errorbar +@image{errorbar,8cm} +@caption{Errorbar plot.} +@end float @DOCSTRING(errorbar) -@DOCSTRING(loglogerr) - @DOCSTRING(semilogxerr) @DOCSTRING(semilogyerr) +@DOCSTRING(loglogerr) + +Finally, the @code{polar} function allows you to easily plot data in +polor coordinates. However, the display coordinates remain rectangular +and linear. For example, + +@example +polar (0:0.1:10*pi, 0:0.1:10*pi); +@end example + +@noindent +produces the spiral plot shown in @xref{fig:polar}. + +@float Figure,fig:polar +@image{polar,8cm} +@caption{Polar plot.} +@end float + +@DOCSTRING(polar) + +The axis function may be used to change the axis limits of an existing +plot. + +@DOCSTRING(axis) + @node Three-Dimensional Plotting -@section Three-Dimensional Plotting +@subsection Three-Dimensional Plotting + +The function @code{mesh} produces mesh surface plots. For example, + +@example +@group +tx = ty = linspace (-8, 8, 41)'; +[xx, yy] = meshgrid (tx, ty); +r = sqrt (xx .^ 2 + yy .^ 2) + eps; +tz = sin (r) ./ r; +mesh (tx, ty, tz); +@end group +@end example + +@noindent +produces the familiar ``sombrero'' plot shown in @xref{fig:mesh}. Note +the use of the function @code{meshgrid} to create matrices of X and Y +coordinates to use for plotting the Z data. The @code{ndgrid} function +is similar to @code{meshgrid}, but works for N-dimensional matrices. + +@float Figure,fig:mesh +@image{mesh,8cm} +@caption{Mesh plot.} +@end float -@DOCSTRING(plot3) +The @code{meshc} function is similar to @code{mesh}, but also produces a +plot of contours for the surface. + +The @code{plot3} function displays arbitrary three-dimensional data, +without requiring it to form a surface. For example + +@example +@group +t = 0:0.1:10*pi; +r = linspace (0, 1, numel (t)); +z = linspace (0, 1, numel (t)); +plot3 (r.*sin(t), r.*cos(t), z); +@end group +@end example + +@noindent +displays the spiral in three dimensions shown in @xref{fig:plot3}. + +@float Figure,fig:plot3 +@image{plot3,8cm} +@caption{Three dimensional spiral.} +@end float + +Finally, the @code{view} function changes the viewpoint for +three-dimensional plots. @DOCSTRING(mesh) @@ -92,37 +226,31 @@ @DOCSTRING(ndgrid) +@DOCSTRING(plot3) + @DOCSTRING(view) -@node Manipulating Existing Plots -@section Manipulating Existing Plots - -@DOCSTRING(axis) - -@DOCSTRING(gca) +@node Plot Annotations +@subsection Plot Annotations -@DOCSTRING(gcf) - -@DOCSTRING(get) - -@DOCSTRING(set) - -@DOCSTRING(ancestor) +You can add titles, axis labels, legends, and arbitrary text to an +existing plot. For example, -@DOCSTRING(clf) - -@DOCSTRING(delete) - -@DOCSTRING(close) +@example +@group +x = -10:0.1:10; +plot (x, sin (x)); +title ("sin(x) for x = -10:0.1:10"); +xlabel ("x"); +ylabel ("sin (x)"); +text (pi, 0.7, "arbitrary text"); +legend ("sin (x)"); +@end group +@end example -@DOCSTRING(closereq) - -@DOCSTRING(ishandle) - -@DOCSTRING(isfigure) - -@node Plot Annotations -@section Plot Annotations +The functions @code{grid} and @code{box} may also be used to add grid +and border lines to the plot. By default, the grid is off and the +border lines are on. @DOCSTRING(title) @@ -137,31 +265,426 @@ @DOCSTRING(grid) @node Multiple Plots on One Page -@section Multiple Plots on One Page +@subsection Multiple Plots on One Page + +Octave can display more than one plot in a single figure. The simplest +way to do this is to use the @code{subplot} function to divide the plot +area into a series of subplot windows that are indexed by an integer. +For example, + +@example +@group +subplot (2, 1, 1) +fplot (@@sin, [-10, 10]); +subplot (2, 1, 2) +fplot (@@cos, [-10, 10]); +@end group +@end example + +@noindent +creates a figure with two separate axes, one displaying a sine wave and +the other a cosine wave. The first call to subplot divides the figure +into two plotting areas (two rows and one column) and makes the first plot +area active. The grid of plot areas created by @code{subplot} is +numbered in column-major order (top to bottom, left to right). @DOCSTRING(subplot) @node Multiple Plot Windows -@section Multiple Plot Windows +@subsection Multiple Plot Windows + +You can open multiple plot windows using the @code{figure} function. +For example + +@example +figure (1); +fplot (@@sin, [-10, 10]); +figure (2); +fplot (@@cos, [-10, 10]); +@end example + +@noindent +creates two figures, with the first displaying a sine wave and +the second a cosine wave. Figure numbers must be positive integers. @DOCSTRING(figure) @node Printing Plots -@section Printing Plots +@subsection Printing Plots + +The @code{print} command allows you to save plots in a variety of +formats. For example, + +@example +print -deps foo.eps +@end example + +@noindent +writes the current figure to an encapsulated PostScript file called +@file{foo.eps}. @DOCSTRING(print) @DOCSTRING(orient) @node Test Plotting Functions -@section Test Plotting Functions +@subsection Test Plotting Functions + +The functions @code{sombrero} and @code{peaks} provide a way to check +that plotting is working. Typing either @code{sombrero} or @code{peaks} +at the Octave prompt should display a three dimensional plot. @DOCSTRING(sombrero) @DOCSTRING(peaks) +@node Advanced Plotting +@section Advanced Plotting + +@menu +* Graphics Objects:: +* Graphics Object Properties:: +* Interaction with gnuplot:: +@end menu + +@node Graphics Objects +@subsection Graphics Objects + +Plots in Octave are constructed from the following @dfn{graphics +objects}. Each graphics object has a set of properties that define its +appearance and may also contain links to other graphics objects. +Graphics objects are only referenced by a numeric index, or @dfn{handle}. + +@table @asis +@item root figure +The parent of all figure objects. The index for the root figure is +defined to be 0. + +@item figure +A figure window. + +@item axes +An set of axes. This object is a child of a figure object and may be a +parent of line, text, image, patch, or surface objects. + +@item line +A line in two or three dimensions. + +@item text +Text annotations. + +@item image +A bitmap image. + +@item patch +A filled polygon, currently limited to two dimensions. + +@item surface +A three-dimensional surface. +@end table + +To determine whether an object is a graphics object index or a figure +index, use the functions @code{ishandle} and @code{isfigure}. + +@DOCSTRING(ishandle) + +@DOCSTRING(isfigure) + +The function @code{gcf} returns an index to the current figure object, +or creates one if none exists. Similarly, @code{gca} returns the +current axes object, or creates one (and its parent figure object) if +none exists. + +@DOCSTRING(gcf) + +@DOCSTRING(gca) + +The @code{get} and @code{set} functions may be used to examine and set +properties for graphics objects. For example, + +@example +@group +get (0) + @result{} ans = + @{ + type = root figure + currentfigure = [](0x0) + children = [](0x0) + visible = on + @} +@end group +@end example + +@noindent +returns a structure containing all the properties of the root figure. +As with all functions in Octave, the structure is returned by value, so +modifying it will not modify the internal root figure plot object. To +do that, you must use the @code{set} function. Also, note that in this +case, the @code{currentfigure} property is empty, which indicates that +there is no current figure window. + +The @code{get} function may also be used to find the value of a single +property. For example, + +@example +@group +get (gca (), "xlim") + @result{} [ 0 1 ] +@end group +@end example + +@noindent +returns the range of the x-axis for the current axes object in the +current figure. + +To set graphics object properties, use the set function. For example, + +@example +set (gca (), "xlim", [-10, 10]); +@end example + +@noindent +sets the range of the x-axis for the current axes object in the current +figure to @samp{[-10, 10]}. Additionally, calling set with a graphics +object index as the only argument returns a structure containing the +default values for all the properties for the given object type. For +example, + +@example +set (gca ()) +@end example + +@noindent +returns a structure containing the default property values for axes +objects. + +@DOCSTRING(get) + +@DOCSTRING(set) + +@DOCSTRING(ancestor) + +You can create axes, line, and patch objects directly using the +@code{axes}, @code{line}, and @code{patch} functions. These objects +become children of the current axes object. + +@DOCSTRING(axes) + +@DOCSTRING(line) + +@DOCSTRING(patch) + +By default, Octave refreshes the plot window when a prompt is printed, +or when waiting for input. To force an update at other times, call the +@code{drawnow} function. + +@DOCSTRING(drawnow) + +Normally, high-level plot functions like @code{plot} or @code{mesh} call +@code{newplot} to initialize the state of the current axes so that the +next plot is drawn in a blank window with default property settings. To +have two plots superimposed over one another, call the @code{hold} +function. For example, + +@example +@group +hold ("on"); +x = -10:0.1:10; +plot (x, sin (x)); +plot (x, cos (x)); +hold ("off"); +@end group +@end example + +@noindent +displays sine and cosine waves on the same axes. If the hold state is +off, consecutive plotting commands like this will only display the last +plot. + +@DOCSTRING(newplot) + +@DOCSTRING(hold) + +@DOCSTRING(ishold) + +To clear the current figure, call the @code{clf} function. To bring it +to the top of the window stack, call the @code{shg} function. To delete +a graphics object, call @code{delete} on its index. To close the +figure window, call the @code{close} function. + +@DOCSTRING(clf) + +@DOCSTRING(shg) + +@DOCSTRING(delete) + +@DOCSTRING(close) + +@DOCSTRING(closereq) + +@node Graphics Object Properties +@subsection Graphics Object Properties +@cindex graphics object properties + +@menu +* Root Figure Properties:: +* Common Properties:: +* Axes Properties:: +* Line Properties:: +* Text Properties:: +* Image Properties:: +* Patch Properties:: +* Surface Properties:: +@end menu + +@node Root Figure Properties +@subsubsection Root Figure Properties + +@table @code +@item currentfigure +@item visible +@end table + +@node Common Properties +@subsubsection Common Properties + +@table @code +@item nextplot +@item closerequestfcn +@item currentaxes +@item colormap +@item visible +@item paperorientation +@end table + +@node Axes Properties +@subsubsection Axes Properties + +@table @code +@item position +@item title +@item box +@item key +@item keybox +@item keypos +@item dataaspectratio +@item dataaspectratiomode +@item xlim +@itemx ylim +@itemx zlim +@itemx clim +@item xlimmode +@itemx ylimmode +@itemx zlimmode +@itemx climmode +@item xlabel +@itemx ylabel +@itemx zlabel +@item xgrid +@itemx ygrid +@itemx zgrid +@item xminorgrid +@itemx yminorgrid +@itemx zminorgrid +@item xtick +@itemx ytick +@itemx ztick +@item xtickmode +@itemx ytickmode +@itemx ztickmode +@item xticklabel +@itemx yticklabel +@itemx zticklabel +@item xticklabelmode +@itemx yticklabelmode +@itemx zticklabelmode +@item xscale +@itemx yscale +@itemx zscale +@item xdir +@itemx ydir +@itemx zdir +@item xaxislocation +@itemx yaxislocation +@item view +@item visible +@item nextplot +@item outerposition +@end table + +@node Line Properties +@subsubsection Line Properties + +@table @code +@itemx xdata +@itemx ydata +@itemx zdata +@itemx ldata +@itemx udata +@itemx xldata +@itemx xudata +@item color +@item linestyle +@item linewidth +@item marker +@item markeredgecolor +@item markerfacecolor +@item markersize +@item keylabel +@end table + +@node Text Properties +@subsubsection Text Properties + +@table @code +@item string +@item units +@item position +@item rotation +@item horizontalalignment +@item color +@end table + +@node Image Properties +@subsubsection Image Properties + +@table @code +@item cdata +@itemx xdata +@itemx ydata +@end table + +@node Patch Properties +@subsubsection Patch Properties + +@table @code +@item cdata +@itemx xdata +@itemx ydata +@itemx zdata +@item facecolor +@item facealpha +@item edgecolor +@item linestyle +@item linewidth +@item marker +@item markeredgecolor +@item markerfacecolor +@item markersize +@end table + +@node Surface Properties +@subsubsection Surface Properties + +@table @code +@item xdata +@itemx ydata +@itemx zdata +@item keylabel +@end table + @node Interaction with gnuplot -@section Interaction with @code{gnuplot} +@subsection Interaction with @code{gnuplot} @DOCSTRING(gnuplot_binary)