Matplotlib scatter plot legend

Question

I created a 4D scatter plot graph to represent different temperatures in a specific area  When I create the legend  the legend shows the correct symbol and color but adds a line through it  The code I m using is   colors   b    c    y    m    r   lo   plt Line2D range 10   range 10   marker  x   color colors 0   ll   plt Line2D range 10   range 10   marker  o   color colors 0   l   plt Line2D range 10   range 10   marker  o  color colors 1   a   plt Line2D range 10   range 10   marker  o  color colors 2   h   plt Line2D range 10   range 10   marker  o  color colors 3   hh   plt Line2D range 10   range 10   marker  o  color colors 4   ho   plt Line2D range 10   range 10   marker  x   color colors 4   plt legend  lo ll l a  h  hh  ho    Low Outlier    LoLo   Lo    Average    Hi    HiHi    High Outlier   numpoints 1  loc  lower left   ncol 3  fontsize 8    I tried changing Line2D to Scatter and scatter  Scatter returned an error and scatter changed the graph and returned an error   With scatter  I changed the range 10  to the lists containing the data points  Each list contains either the x  y  or z variable   lo   plt scatter xLOutlier  yLOutlier  zLOutlier  marker  x   color colors 0   ll   plt scatter xLoLo  yLoLo  zLoLo  marker  o   color colors 0   l   plt scatter xLo  yLo  zLo  marker  o  color colors 1   a   plt scatter xAverage  yAverage  zAverage  marker  o  color colors 2   h   plt scatter xHi  yHi  zHi  marker  o  color colors 3   hh   plt scatter xHiHi  yHiHi  zHiHi  marker  o  color colors 4   ho   plt scatter xHOutlier  yHOutlier  zHOutlier  marker  x   color colors 4   plt legend  lo ll l a  h  hh  ho    Low Outlier    LoLo   Lo    Average    Hi    HiHi        High Outlier   scatterpoints 1  loc  lower left   ncol 3  fontsize 8    When I run this  the legend no longer exists  it is a small white box in the corner with nothing in it    Any advice

User · Answer

Other answers seem a bit complex  you can just add a parameter  label  in scatter function and that will be the legend for your plot  import matplotlib pyplot as plt from numpy random import random  colors     b    c    y    m    r    lo   plt scatter random 10   random 10   marker  x   color colors 0  label  Low Outlier   ll   plt scatter random 10   random 10   marker  o   color colors 0  label  LoLo   l    plt scatter random 10   random 10   marker  o   color colors 1  label  Lo   a    plt scatter random 10   random 10   marker  o   color colors 2  label  Average   h    plt scatter random 10   random 10   marker  o   color colors 3  label  Hi   hh   plt scatter random 10   random 10   marker  o   color colors 4  label  HiHi   ho   plt scatter random 10   random 10   marker  x   color colors 4  label  High Outlier    plt legend loc  upper center   bbox to anchor  0 5  -0 05             fancybox True  shadow True  ncol 4   plt show    This is your output

User · Answer

2D scatter plot Using the scatter method of the matplotlib pyplot module should work  at least with matplotlib 1 2 1 with Python 2 7 5   as in the example code below  Also  if you are using scatter plots  use scatterpoints 1 rather than numpoints 1 in the legend call to have only one point for each legend entry  In the code below I ve used random values rather than plotting the same range over and over  making all the plots visible  i e  not overlapping each other   import matplotlib pyplot as plt from numpy random import random  colors     b    c    y    m    r    lo   plt scatter random 10   random 10   marker  x   color colors 0   ll   plt scatter random 10   random 10   marker  o   color colors 0   l    plt scatter random 10   random 10   marker  o   color colors 1   a    plt scatter random 10   random 10   marker  o   color colors 2   h    plt scatter random 10   random 10   marker  o   color colors 3   hh   plt scatter random 10   random 10   marker  o   color colors 4   ho   plt scatter random 10   random 10   marker  x   color colors 4    plt legend  lo  ll  l  a  h  hh  ho                Low Outlier    LoLo    Lo    Average    Hi    HiHi    High Outlier               scatterpoints 1             loc  lower left              ncol 3             fontsize 8   plt show     3D scatter plot To plot a scatter in 3D  use the plot method  as the legend does not support Patch3DCollection as is returned by the scatter method of an Axes3D instance  To specify the markerstyle you can include this as a positional argument in the method call  as seen in the example below  Optionally one can include argument to both the linestyle and marker parameters  import matplotlib pyplot as plt from numpy random import random from mpl toolkits mplot3d import Axes3D  colors   b    c    y    m    r    ax   plt subplot 111  projection  3d    ax plot random 10   random 10   random 10    x   color colors 0   label  Low Outlier   ax plot random 10   random 10   random 10    o   color colors 0   label  LoLo   ax plot random 10   random 10   random 10    o   color colors 1   label  Lo   ax plot random 10   random 10   random 10    o   color colors 2   label  Average   ax plot random 10   random 10   random 10    o   color colors 3   label  Hi   ax plot random 10   random 10   random 10    o   color colors 4   label  HiHi   ax plot random 10   random 10   random 10    x   color colors 4   label  High Outlier    plt legend loc  upper left   numpoints 1  ncol 3  fontsize 8  bbox to anchor  0  0    plt show

User · Answer

if you are using matplotlib version 3 1 1 or above  you can try   import matplotlib pyplot as plt from matplotlib colors import ListedColormap  x    1  3  4  6  7  9  y    0  0  5  8  8  8  classes     A    B    C   values    0  0  1  2  2  2  colours   ListedColormap   r   b   g    scatter   plt scatter x  y c values  cmap colours  plt legend handles scatter legend elements   0   labels classes

User · Answer

Here s an easier way of doing this  source  here    import matplotlib pyplot as plt from numpy random import rand   fig  ax   plt subplots   for color in   red    green    blue        n   750     x  y   rand 2  n      scale   200 0   rand n      ax scatter x  y  c color  s scale  label color                 alpha 0 3  edgecolors  none    ax legend   ax grid True   plt show     And you ll get this     Take a look at here for legend properties

[python] Matplotlib scatter plot legend

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