I would like to visualize a 3D scalar field as given by a dataset which has the following format:
x y z f(x,y,z)
That is, my dataset consists of four columns where the first three columns denote a position and the fourth column the value of the scalar field at that position.
Is there a fast and easy way of generating a contour plot from such a dataset? I have been looking into gnuplot, but I have not been able to figure out how to create a simple contour plot from my dataset, though it looks to me it should be possible.
Gnuplot can handle only 3D-data, i.e. x, y, f(x, y). A fourth dimension can be applied only in form of a color information.
Related
I wanted to display my data from my Excel spreadsheet graphically, in the form of a scatter chart.
I know that Excel can do this, but there is one "special feature" about my coordinate system of my graphic, and that is that one of the axes should be labeled with "words" (instead of numbers) to match my table similar to the picture. But I am not sure if Excel can process this at all, I guess that Excel can only work with numbers on the axes.
I would be very grateful for any help and tips and also alternatives!
By definition, the axes in an XY Scatter plot are numeric. But your desired chart can easily be created by adding a helper series to the plot. Assuming the current Y values for the other series are the numbers 1 to 6 for even positioning, you can use a range with Y values 1 to 6 and X values of zero and add that data range as a new series to the plot.
The plot points will sit right on the Y axis. Remove the Y axis labels in the Axis formatting options. You can then use data labels from the worksheet and position them to the left of the plot points of the helper series. Finally, format the markers of the helper series to have no fil and no line to make them invisible.
I am trying to understand the distribution of my data for a particular column. It has close to ~1 Million records.
Here is the code that I have written to see the density plot.
df[ "ratio"].plot.kde(bw_method=0.1) # Plot continuous column
https://wellsr.com/python/python-pandas-density-plot-from-a-dataframe/
Here is the plot that I get:
I am not clear what does x-axis and y-axis indicate?
Is x-axis the ratio values from dataframe?
What does Density means in y-axis and how it is calculated?
Do we have any such formula to derive this values in y-axis? I am more interested in deriving the values. Given the column ratio how can we come up with density values. Can someone quickly show the maths?
If you are plotting a KDE, it means you are plotting a Probabilistic Density Function (PDF) of a random variable.
The X-Axis will be the range of values of the parameter you are plotting for. In your case, since you are plotting for Ratio, X-Axis will represent the range of values of your parameter ratio
Y-Axis on the other hand represents kernel density i.e the probability of the parameter your are plotting for.
Read the documentation
I have a three column data; I want to plot a scatterplot with the first two columns and colormap the data along the third axis. How can this be done using any of the plotting modules available with python ?
The following code
a= np.random.randn(100)
b=np.random.randn(100)
sns.jointplot(a,b)
produces
What is the histogram on the top and right hand side?
And how do I read this graph?
The histogram on the top shows the distribution of the variable at the x-axis and the histogram to the right shows the distribution of the variable at the y-axis.
And the scatter plot is the usual x=a Vs y=b. Hope it helps.
Dataser a's x axis also becomes x axis of the joint plot, database b's x axis becomes y axis of the joint plot. Graph on top and rhs, are same as the individual histogram. The graph is continuous, and changes on bin change, unlike histogram where it may be discontinuous
I am trying to plot predictions vs observations in a scatter plot showing the predicted values in x and the observed in y, so a perfect fit should be shown in the diagonal. Is there any way to plot that diagonal in excel as a line, so it is easier to see if the result is close to the ideal? Also, my model has a standard error that I would also like to show as upper and lower line. Something like this:
Any ideas how I could add the lines in excel? Thanks !!
[edit]
This happens if I add a new series to draw the diagonal line as a line plot:
Where 'line 1' gives me what is shown in the center image after I add a new series, and 'line 2' the one of the right if I add the cells to a existing axis. What I'm doing wrong? thanks
Create a new series for each line, with just two points for each series.
For the diagonal, the first point is at the intersection of the axes and the second is at the top right of the charted area. Format the series with a suitable line and no data points.
For the upper and lower lines, same technique but the first point is where the line intersects the y or x axis respectively.