The values in y can be numeric, datetime, duration, or categorical values. With your original code, the units will be in terms of logxa. You can plot the data in a 2d or 3d view using either a linear or a logarithmic scale. Specify name,value as the last pair of arguments in any of the previous syntaxes. Create plots programmatically using graphics functions or interactively using the plots tab at the top of the matlab desktop. Xyz contour plot with colormap from second z and custom. If, hypothetically, it were able to display with complex coordinates, where would you want the values displayed. Colorbar showing color scale matlab colorbar mathworks france. Contour chart appearance and behavior matlab mathworks italia. Jul 06, 2012 the ability to create a logarithmic scale colormap or colorbar is not available in matlab. For example do you want the complex portion of the coordinate to be treated as time, and the display should automatically cycle through a time period perhaps every 2pi seconds with the negative values being displayed for one frame on each occasion that the complex value projected. To create a plot using a log base 10 scale for both the xaxis and and the yaxis you can use the function loglog. Create a second contour plot and use zindex to highlight contour lines at every other integer value.
Generate logarithmically spaced vector matlab logspace. This example shows how to change the colors used in a filled contour plot. The column and row indices of z are the x and y coordinates in the plane, respectively. Contourf and log color scale demonstrate use of a log color scale in contourf import matplotlib. Hi, i would like to know how can i apply the same thing for the contourf. Add a line plot to the axes by specifying the uiaxes object as the first input argument for the plot function. The contour matrix, c, is an optional output argument returned by contour, contour3, and contourf. I have several different contour plots, and therefore i need them with the same color scale. Ive read all the help on contour and contourf functions and colorbar but nothing useful can be found there.
The logspace function is especially useful for creating frequency vectors. For example, you can compare sets of data, track changes in data over time, or show data distribution. Define scale in contourplot matlab answers matlab central. The clabel function uses values from c to display labels for 2d contour lines. May 24, 20 however setting the range of b or a to b0. Is it possible to make contour graph with a semilogy scale. I would like to make 3d plot using mesh in which one axis should be on a logarithmic scale. I sometimes require a plot which has a colorbar with a log scale. Im currently doing some simulation work for a physics honours project and i have data generated into vectors that id like to plot. Is there a way to use meshgrid and mesh to do this.
If you are working with polar axes, then this option sets thetalimmode and rlimmode to manual. Matlab evaluates the variable in the base workspace to generate the xdata. Matlab lesson 10 log scale plots university of new south. Logarithmic scale for colorbar matlab answers matlab central. Learn more about logarithmic, nonlinear, non, linear, log, scale matlab.
I have a workaround where i plot the log data in the contour and replace the x and ytick labels of the plot. You can create a contour plot with emphasis on selected contour lines by splitting the data and creating two overlapping contour plots. Set axis limits and aspect ratios matlab axis mathworks. Plotting a scatter plot with logarithmic axes matlab. Contourf and log color scale demonstrate use of a log color scale in contourf. Logarithmic scale for colorbar matlab answers matlab. The log of negative real values is equal to the log of the positive value, plus pi1i that is the result is complex. Not all types of charts support modifying the colorbar appearance. Contour plot color scaling matlab answers matlab central. This term refers to the fact that the plot is logarithmically scaled in both axes. Semilog plot yaxis has log scale matlab semilogy mathworks. Matlab lesson 10 log scale plots university of new. However, what is interesting to see is between 0 and 0.
The ability to create a logarithmic scale colormap or colorbar is not available in matlab. By default, there is no linked variable so the value is an empty character vector. Previously i did this by setting the yscale property of the underlying colorbar axes, but this no longer works with the new graphics system. The matlab mfile used to create this plot is experr. When you set yscale to log, then internally it would take the log of the negative values you have, and would found that the log is complex. Downloads trial software contact sales pricing and licensing how to buy. Jul 09, 2014 if i use imrotate for the matrix i have of the contour, the resultant contour doesnt actually rotate by the same angle which i specify 37 deg in the example, image3 and more over sometimes the width of the plot decreases. A fellow customer posted the following suggested workaround for this problem on our usenet newsgroup, comp.
Learn more about logarithmic, nonlinear, non, linear, log, scale. Nov 03, 2014 does anybody know how to get nice contourlabels clabel in plots with logaritmic axes. To create a plot with a linear scale on the xaxis and a log base 10 scale on the xaxis you can use the function semilogx. Ive read up on the scatter function, but havent seen how to plot any of those axes in a logarithmic fashion.
Is it possible to make contour graph with log scale colorbar. To force an update of the data values, use the refreshdata function. For illustrations of some of the types of plots you can create programmatically, see types of matlab plots. I would like to make contourf plot but in such a way that the colorbar is in log scale because i have quite a large range of values in my data. Here are some matlab code of active contour model, which are collected from the internet. Display eight contour levels of the peaks function and label the contours. Logarithmic colorbar for contour plot a lot of my data ranges orders of magnitude, and can be very hard to depict using standard matlab functions like imagesc, contourf, contour, etc. But regardless, id like to only have the y axis as a log scale, not the whole plot. All values in the colormap indexing array that are less than or equal to cmin map to the first row in the colormap.
Is it possible to make contour graph with log scale. However, if the axes hold state is on before you call loglog, those properties do not change, and the plot might display on a linear or semilog scale. Rotation of a contour plot matlab answers matlab central. For example, direction,reverse reverses the color scale. If you link a variable, then matlab does not update the xdata values immediately. However i am not happy with result because the labeling does work during zoom. Aug 09, 2012 i would like to make contourf plot but in such a way that the colorbar is in log scale because i have quite a large range of values in my data.
The function is the logarithmic equivalent of linspace and the. Matlab automatically selects the contour lines to display. Mar 16, 2012 a lot of my data ranges orders of magnitude, and can be very hard to depict using standard matlab functions like imagesc, contourf, contour, etc. Meshgrid for logarithmic scales matlab answers matlab central. Im currently trying to plot data using contourfx,y,z, where z values are ranging from 0. Please see more details on creating and customizing color fill contour in the 3d and contour graphing chapter. Use only the colors in the center of the hot colormap by setting the color axis scaling to a range much larger than the range of values in matrix z. Find a way to set the logarithmic scale programmatically and let matlab worry about the isolines.
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