Each option divides the 2D plot’s Z data, i.e., the event count at each X, Y point, and divides all visible events into the selected Levels option percentages. The Style sidebar allows you to adjust the color combo box to black or color with a dropdown menu and the Levels combo box has options for: “10% (10 levels)”, “5% (20 levels)”, or “2% (50 levels)”. If necessary, you can disable the contour plot display by altering the colors and percent of the cell levels by viewing the settings tab and searching for the Style sidebar. The contour plot clearly displays two distinct cell populations in the All Beads and Cells populations. When you are in the analysis tab and open a default All Events plot, you may then right click and select the Add Contour Plot icon in the dropdown.Īs shown in the following screen shot, two previously gated populations named All Beads and Cells are now displayed as a. We will use the colormap “RdBu”.A contour plot is a graphical technique for rendering 3-dimensonal surface by plotting constant z slices, called contours, in a 2-dimensional format Except as noted, function signatures and return values are the same for both versions. Take a moment and think of which class of color maps would be best for this type of data.Īfter some consideration, you should arrive at the conclusion that we should use a diverging colormap to best represent this data. Call signature: contour( X, Y, Z, levels, kwargs) contour and contourf draw contour lines and filled contours, respectively. This data has both positive and negative values, which zero representing a node for the wavefunction. Qualitative: often are miscellaneous colors should be used to represent information which does not have ordering or relationships. A contour plot is constructed from three variables. Sequential: change in lightness and often saturation of color incrementally, often using a single hue should be used for representing information that has ordering.ĭiverging: change in lightness and possibly saturation of two different colors that meet in the middle at an unsaturated color should be used when the information being plotted has a critical middle value, such as topography or when the data deviates around zero.Ĭyclic: change in lightness of two different colors that meet in the middle and beginning/end at an unsaturated color should be used for values that wrap around at the endpoints, such as phase angle, wind direction, or time of day. Contour plots are topographical maps drawn from three-dimensional data. Matplotlib gives the following guidance (see, e.g., Moreland): There are different classes of colormaps you might want to choose depending on the type of data you are looking at. You can see a list of built-in color maps for matplotlib here. When creating a contour plot, you can also specify the color map you would like to use.
#Contour plot download#
We will have to use the slicing syntax with the iloc function which was discussed in the first section on pandas dataframes. Download Python source code: contour.py Download Jupyter notebook: contour.
![contour plot contour plot](https://i.stack.imgur.com/fZvdd.png)
We will pull out the x values, the y values and the data (or the z values as separate variables. For example, at the point (-20, -20), the wavefunction has the value 0.000353. The first row represents x values, and the first column represents y values. Here is the formal definition of a contour plot: A level curve of a function f (x,y) is the curve of points (x,y) where f. Some of the resultant contours can be a straight line as well. Each contour is a curve that is a resultant of cutting a surface by a plane. You would not automatically know this from looking at the data file, but it is structured in a specific way. Contour plot is a collection of contour lines. We are going to do some additional slicing on this data in order to plot it. The file we are reading in this time does not have headers, so we must tell pandas that there are no headers when we read the data file in.
![contour plot contour plot](https://static.packt-cdn.com/products/9781849513067/graphics/3067_08_07.jpg)
Notice that this time, our function read_csv has not behaved exactly as we would want.