small ant 12 Tháng tư 2011 - #1 Figures, Plots, and Graphs (Lượt xem: 1,005) What Is a MATLAB Graph? The MATLAB environment offers a variety of data plotting functions plus a set of GUI tools to create, and modify graphic displays. The GUI tools afford most of the control over graphic properties and options that typed commands such as annotate, get, and set provide. A figure is a MATLAB window that contains graphic displays (usually data plots) and UI components. You create figures explicitly with the figure function, and implicitly whenever you plot graphics and no figure is active. By default, figure windows are resizable and include pull-down menus and toolbars. A plot is any graphic display you can create within a figure window. Plots can display tabular data, geometric objects, surface and image objects, and annotations such as titles, legends, and colorbars. Figures can contain any number of plots. Each plot is created within a 2-D or a 3-D data space called an axes. You can explicitly create axes with the axes or subplot functions. A graph is a plot of data within a 2-D or 3-D axes. Most plots made with MATLAB functions and GUIs are therefore graphs. When you graph a one-dimensional variable (e.g., rand(100,1)), the indices of the data vector (in this case 1:100) become assigned as x values, and plots the data vector as y values. Some types of graphs can display more than one variable at a time, others cannot. The contents and varieties of figures, plots and graphs that MATLAB can make are explained in the following sections. Back to Top Anatomy of a Graph MATLAB plotting functions and tools direct their output to a figure window. Each figure is a separate window that you can dock in the desktop, and collect together with other plots in a Figure Group. To illustrate the basic components of a graph, execute the following code to create a plot of a family of sine curves: x = [0:.2:20]; y = sin(x)./sqrt(x+1); y(2, = sin(x/2)./sqrt(x+1); y(3, = sin(x/3)./sqrt(x+1); plot(x,y)The resulting figure contains a 2-D set of axes. This graphic identifies the components and tools of a figure window. The plot function uses a default line style and color to distinguish the data sets plotted in the graph. You can change the appearance of these graphic components or add annotations to the graph to present your data in a particular way. Back to Top Figure Toolbars Figure toolbars provide shortcuts to access commonly used features. These include operations such as saving and printing, plus tools for interactive zooming, panning, rotating, querying, and editing plots. The following picture shows the features available from this toolbar. You can enable two other toolbars from the View menu: Camera Toolbar — Use for manipulating 3-D views. See View Control with the Camera Toolbar in the MATLAB 3-D Visualization documentation for more information. Plot Edit Toolbar — Use for annotation and setting object properties. See Annotation Tools on the Plot Edit Toolbar for more information. Back to Top Types of MATLAB Plots You can construct a wide variety of 2-D and 3-D MATLAB plots with very little, if any, programming required on your part. The following two tables classify and illustrate most of the kinds of plots you can create. They include line, bar, area, direction and vector field, radial, and scatter graphs. They also include 2-D and 3-D functions that generate and plot geometric shapes and objects. Most 2-D plots have 3-D analogs, and there are a variety of volumetric displays for 3-D solids and vector fields. Plot types that begin with "ez" (such as ezsurf) are convenience functions that can plot arguments given as functions. Two-Dimensional Plotting Functions The table below shows all available MATLAB 2-D plot functions. If you are reading this online, you can click any icon to see the documentation for that function. Techniques for using many of the functions are also discussed in later sections of this document. Line GraphsBar GraphsArea GraphsDirection GraphsRadial GraphsScatter Graphs plot bar (grouped) area feather polar scatter plotyy barh (grouped) pie quiver rose spy loglog bar (stacked) fill comet compass plotmatrix semilogx barh (stacked) contourf ezpolar semilogy hist image stairs pareto pcolor contour errorbar ezcontourf ezplot stem ezcontour Three-Dimensional Plotting Functions The table below shows all available MATLAB 3-D and volumetric plot functions. It includes functions that generate 3-D data (cylinder, ellipsoid, sphere), but most plot either arrays of data or functions. If you are reading this online, you can click any picture in the table to see the documentation for that function. For information about and examples of using 3-D plotting functions, see Creating 3-D Graphs in the 3-D Visualization documentation. Line GraphsMesh Graphs and Bar GraphsArea Graphs and Constructive ObjectsSurface GraphsDirection GraphsVolumetric Graphs plot3 mesh pie3 surf quiver3 scatter3 contour3 meshc fill3 surfl comet3 coneplot contourslice meshz patch surfc streamslice streamline ezplot3 ezmesh cylinder ezsurf streamribbon waterfall stem3 ellipsoid ezsurfc streamtube bar3 sphere bar3h Choosing a Plot Type Interactively You can interactively generate any of the plotting functions shown in the previous tables using the Plot Selector and Plot Catalog tools: Select one or more numeric workspace variables in the Workspace Browser, the Variable Editor or the plotting tools Figure Palette. Open the Plot Selector or Plot Catalog tool and scroll to the name or icon of the type of graph you want to create. Alternatively, right-click a selected variable and choose Plot Catalog from the context menu. You can enter a search term in either tool to locate a graph by function name or other identifying information. Click the icon to plot the selected variables. The graph displays in the current figure, and the command that generated it displays in the Command Window. You can choose any type of MATLAB plot and plots from several toolboxes. You need a license for a toolbox in order for its plot types to display in the tools. If you select a graphics function that is not able to plot the selected variables, the entry for that plot type turns gray and a diagnostic message pops up when you hover over it.