I ' mgettingquitedesperateaboutthis，icouldn ' tfindanythingonthewwsofar。
Here's the situation:
I am working with Python。
Ihave3arrays : the x-coordinates，the y-coordinates and the radius。
iwanttocreateascatterplotwiththegivenx-Andy-coordinates。
So far，everythingworkshowiwantitto.hereiswhat ' sbotheringme :
thecirclesizeofeachpointinthescatterplotshouldbedefinedbytheradiusarray。
thethevaluesofthecoordinatesandtheradiusareinsameunits.more explicitly : let ' sassumeihaveapointat (1， 1 ) with radius 0.5 assigned.theniwanttogetacircleintheplotcenteredat (1，1 ) andwiththebordergoingthroughtthepoints (1.5，1 )
watiamstrugglingwithistofindouttheratioofplotpointstothelengthinanaxis.ineedtoworkwithpointsbecauseasfarasicansee， thecirclesizeofthescatterplotisgiveninpointvalues.soif let ' ssaymyaxisgoesfrom0to 10，ineedtoknowhowmanypointststhereareareareinbetwetwetwetwetwbetwetwetwettttwer
Can anybody help me？ Or is there another way of doing this？
高级thanks in。
解决方案
I ' mjumpinginfromyourotherstackoverflowquestion.ithinktheapproachyoupresentedasanswertothepresentquestionwon ' tworkexaction
First，the size of the markers is in points，not in pixels. In typography，thepointisthesmallestunitofmeasureandcorrespondinmatplotol
Second，thesizeofthemarkersinplt.scatterarerelatedtothediameterofthecircles，not the radius。
sothesizeinpointsofeachmarkershouldbecalculatedas :
size _ in _ points=(2* radius _ in _ pixels/fig _ dpi * 72 points/inch ) **2
移动器，as shown in the MWE below，itispossibletocalculatethesizeofthemarkerradiusinpixelsdirectlywithmatplotlibtransformations
import numpy as np
import matplotlib.pyplot as plt
PLT.close(all ) )。
# Generate some data :
N=25
x=NP.random.rand(n ) 0.5
y=NP.random.rand(n ) 0.5
r=NP.random.rand(n )/10
#打印the data :
fig=PLT.figure (face color=' white '，fig size=(7，7 ) )
scat=ax.Scatter(x，y，s=0，alpha=0.5，clip_on=False ) ) ) ) ) ) )。
# Draw figure :
fig.canvas.draw (
# Calculate radius in pixels :
RR_pix=(ax.transdata.transform ) NP.v堆叠([ r，r] ).t ) -
rpix，_=rr_pix.T
# calculateandupdatesizeinpoints :
size_pt=(2*rpix/fig.dpi*72 ) *2
sat.set_sizes(size_pt ) )。
#保存并显示图形：
fig.save fig (scatter _ size _ axes.png ) )
plt.show () )
apoint at (1，1 ) with radius 0.5 assignedwillresultinacircleintheplotcenteredat ) 1，1 ) andwiththebordergoingthepointhe