Onpick3 悬停最近的数据点而不是列表

Question

经过几天的努力解决这个问题，我想我会寻求帮助...

我有 3 个列表，lon、lat 和 pop 的长度都相同。用lon[1],lat[1]对应pop[1]。我想做的是，在将它们绘制出来之后，到 'hover over the map' 然后（最终为每个点绘制人口的时间序列）但现在，我只想知道相应的人口值是什么.. .

下面一直在用这个，不知道怎么用

a) 使其到达最近的经纬度点，因为当前它会生成一个可能选项列表

b) 放大图形然后单击，因为单击放大按钮似乎会停止记录任何进一步的点...

#Import modules

import netCDF4 as nc4
from netCDF4 import Dataset
import matplotlib.pyplot as plt
import numpy as np
from mpl_toolkits.basemap import Basemap
from matplotlib import cm as cm
from matplotlib import mlab as ml
import matplotlib as mpl
from matplotlib.pyplot import figure, show

def extractdata(nc_filename,column_data):
    dataset=Dataset(nc_filename)    #Reads the data into a column format 
    output= dataset.variables[column_data][:]
    dataset.close()

    return(output)

#Start of program

inputfile='reference_pop.nc'
dataset = Dataset(inputfile)
print(dataset.variables.keys())

time=extractdata(inputfile,'time')
lon=extractdata(inputfile,'lon')
lat=extractdata(inputfile,'lat')
pop=extractdata(inputfile,'pop')



index=np.arange(len(lat))

#Reverse the time order (So that 0 is 120,000 years ago aka from past to present
time=time[::-1]
#Reverse population order 
pop=pop[::-1]   #Population is a 2d matrix, of dimensions pop and len(lon/lat)



def onpick3(event):
    ind = event.ind
    #print 'onpick3 scatter:', ind, npy.take(lon, ind), npy.take(lat, ind)
    print 'ind', ind    #Example output: [2513 2673 2843 3022 3023 3024 3025 3203]
    print 'npy.take(lon, ind)',npy.take(lon, ind)  #Example output [ 21398764.  21459962.  21520490.  21391092.  21454742.  21517902.  21580542.  21577006.]
    print 'npy.take(lat, ind)',npy.take(lat, ind)   #Example output [ 21398764.  21459962.  21520490.  21391092.  21454742.  21517902.  21580542.  21577006.]

    #Will need to reverse back from basemap lat,lon to normal but that is easy


fig = figure()
ax1 = fig.add_subplot(111)


map1 = Basemap(projection='mill',lon_0=0, ax=ax1)

map1.drawmapboundary(fill_color='#9999FF')
##mapping coordinates according to basemap
lon,lat=map1(lon,lat)

ax1.scatter(lon,lat,c=index,cmap=mpl.cm.get_cmap('jet'),picker=1)

fig.canvas.mpl_connect('pick_event', onpick3)

plt.show()

非常感谢您的帮助！

Answer 1

我可能做的很绕，但结果是当我悬停在（放大的地图）上时它只记录了一个点）但是当我很远的时候，这个点包含了几个，在这一点，考虑到地图的密度并且它不会有什么区别，我只是选择了列表中的第一个索引。

def hover(event):

    #Returns a dictionary
    cont, ind = sc.contains(event)

    #Turn dictionary into a list
    myList = []  
    for k,v in ind.items():
        myList.append(v[0])

    #Take first element as it really doesn't matter, as the indexes are so close together 
    ind=myList[0]
fig1.canvas.mpl_connect("motion_notify_event", hover)

Onpick3 悬停最近的数据点而不是列表

Onpick3 Hover nearest data point rather than list

python

matplotlib

scatter-plot

matplotlib-basemap