However, the result says 'QuiverKey' object is not subscriptable. I think that it is because I don't understand fully about these two functions or just these two functions don't match together.
Below is my code, it is actually the combination between quiver and animation functions from matplotlib. Learn more. Plotting animated quivers in Python Ask Question. Asked 6 years, 6 months ago. Active 2 years, 4 months ago. Viewed 10k times. Benjamin Isaac Isaac 2 2 gold badges 9 9 silver badges 25 25 bronze badges. Well, data is a QuiverKey object - it represents a key to a quiver plot, not an array of values that you can index into.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Happy new year everyone! I'm trying to superpose the plots of scalar and vector fields using Matplotlib 's quiver and pcolormesh.
The data I would like to represent is organized in a file of five columns, the first two are the nodes coordinates x and y which are equally spaced. The following two are the vector field components vx and vyand finally the last column gives the values of the scalar field v used with color map. I would like to precise that the nodes with zero vx and vz should not be included in the scalar map.
Learn more. Vector and scalar fields in Matplotlib Ask Question. Asked 2 years, 3 months ago.Flow Modeling in Python I: Vector calculus, potential flow, stream function
Active 2 years, 3 months ago. Viewed times. Here is a sample of my data file: 0. Tom de Geus 3, 1 1 gold badge 17 17 silver badges 44 44 bronze badges.
Sidi M. Khefif Sidi M. Khefif 11 3 3 bronze badges. What isn't working? What have you tried? To get you started: read data from fileconvert it to floats after splitingand then try and plot it. Please read minimal reproducible example. Active Oldest Votes. Hoping it's useful to anyone else looking for it: import matplotlib. Sign up or log in Sign up using Google.
Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. The Overflow How many jobs can be done at home? Featured on Meta. Community and Moderator guidelines for escalating issues via new response….Stream plot is basically a type of 2D plot used majorly by physicists to show fluid flow and 2D field gradients.
The basic function to create a stream plot in Matplotlib is:. All the streamlines are parallel and pointing towards the right. The code below creates the stream plot containing horizontal parallel lines pointing to the right:. Here, x and y are 1D arrays on an evenly spaced grid, u and v are 2D arrays of velocities of x and y where the number of rows should match with the length of y while the number of columns should match with x, density is a float value which controls the closeness of the stream lines.
With the help of streamplot function we can create and customize a plot showing field lines based on defined 2D vector field. Many attributes are available in streamplot function for the modification of the plots. Example: Stream plot to demonstrate the electric field due to two point charges. The electric field at any point on a surface depends upon the position and distance between the two charges:. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.
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Please use ide. The basic function to create a stream plot in Matplotlib is: ax. Import libraries. Varying the density along a. Varying color along a streamline. Varying line width along a streamline. Controlling the starting points. Displaying the starting points. Function to determin electric field. Create a multipole with nq charges of. Increase the power with increase in charge.Where XY define the arrow locations, UV define the arrow directions, and C optionally sets the color.
The default settings auto-scales the length of the arrows to a reasonable size. The defaults give a slightly swept-back arrow; to make the head a triangle, make headaxislength the same as headlength. To make the arrow more pointed, reduce headwidth or increase headlength and headaxislength. To make the head smaller relative to the shaft, scale down all the head parameters.
You will probably do best to leave minshaft alone. If not given, they will be generated as a uniform integer meshgrid based on the dimensions of U and V. In this case len X and len Y must match the column and row dimensions of U and V.
Numeric data that defines the arrow colors by colormapping via norm and cmap. This does not support explicit colors.
How to plot a simple vector field in matplotlib ?
If you want to set colors directly, use color instead. The arrow dimensions except for length are measured in multiples of this unit. The arrows scale differently depending on the units.
For 'x' or 'y', the arrows get larger as one zooms in; for other units, the arrow size is independent of the zoom state. For 'width or 'height', the arrow size increases with the width and height of the axes, respectively, when the window is resized; for 'dots' or 'inches', resizing does not change the arrows. Use this if the arrows symbolize a quantity that is not based on XY data coordinates. Use this for plotting a gradient field, for example. Alternatively, arbitrary angles may be specified explicitly as an array of values in degrees, counter-clockwise from the horizontal axis.
Number of data units per arrow length unit, e. Default is None. If Nonea simple autoscaling algorithm is used, based on the average vector length and the number of vectors.
If the scale kwarg is Nonethe arrow length unit. Shaft width in arrow units; default depends on choice of units, above, and number of vectors; a typical starting value is about 0. Length below which arrow scales, in units of head length.
Do not set this to less than 1, or small arrows will look terrible! Minimum length as a multiple of shaft width; if an arrow length is less than this, plot a dot hexagon of this diameter instead.
The part of the arrow that is anchored to the XY grid. The arrow rotates about this point. Explicit color s for the arrows. If C has been set, color has no effect. This is a synonym for the PolyCollection facecolor parameter. All other keyword arguments are passed on to PolyCollection :.
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Here is my code:. Learn more. How to plot a vector field over a contour plot in matplotlib? Ask Question. Asked 3 years, 4 months ago. Active 3 years, 4 months ago. Viewed 5k times. Here is my code: from matplotlib. Active Oldest Votes.
You have two issues: Calling plt. Simple fix! Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. The Overflow How many jobs can be done at home? Featured on Meta. Community and Moderator guidelines for escalating issues via new response….
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Dark Mode Beta - help us root out low-contrast and un-converted bits.Matplotlib provides a function, streamplotto create a plot of streamlines representing a vector field. The following program displays a representation of the electric field vector resulting from a multipole arrangement of charges.
It requires Matplotlib 1. What clever program, Loved it. I had to change the 'inferno' to 'hot' as we were warned in the opening comments. Didn't realise I was using an outdated version of matplotlib. Sincerly Steven Armour. I'd be happy to take a look at the Notebook you are preparing for your EM class. Best wishes, Christian.
Hi Youcef, The program expects the user to provide the order of the multipole on the command line e. Hello again Christian, I did what you told me and it worked, so thanks a lot for the help and the quick response! Hello Christian, I am a beginner in python, what do you exactly would write in the code for a dipole? I know you already answered the question but i need you to be more specific please. I hope that helps, Christian. Is it possible to get the coordinates of the different streamlines?
Also how can I interpolate between the streamlines? I changed the previous code to use np. I've fixed it now. Cheers, Christian. This is a nice code! But I have one question: Not any steamline is equal. This is seen in your ocutpole right top, red polewhere one steamline is straight.
I want all lines look equally. Do you know how to do this? Cheers, mattes. Toggle Navigation. Everything Blog posts Pages. Posted by: christian on 10 Dec 20 comments Matplotlib provides a function, streamplotto create a plot of streamlines representing a vector field.
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