没有使用Python / Basemap绘制图形的线条

Question

很抱歉，如果这个问题很简单，我就是使用Python和Basemap的新手。无论如何，我试图在地图上绘制20个飓风的路径（图）。地图本身和传说完美呈现，但飓风的路径却没有。此外，我没有得到任何追溯消息，但我想我已经知道我的问题可能在哪里。有人可以告诉我哪里出错了。

以下是csv文件的示例：

Year, Name, Type, Latitude, Longitude
1957,AUDREY,HU, 21.6, 93.3
1957,AUDREY,HU,22.0,  93.4
1957,AUDREY,HU,22.6,  93.5
1969,AUDREY,HU,28.2,99.6
1957,AUDREY,HU,26.5,93.8
1957,AUDREY,HU,27.9,93.8
1957,AUDREY,HU,29.3,95
1957,AUDREY,HU,27.9,93.8
1957,AUDREY,HU,29.3,93.8
1957,AUDREY,HU,30.7,93.5
1969,CAMILLE,HU, 21.6,99.3
1969,CAMILLE,HU,22.0,98.4
1969,CAMILLE,HU,22.6,90.5
1969,CAMILLE,HU,23.2,93.6

这是我到目前为止的代码：

import numpy as np
from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt
import csv, os, scipy
import pandas
from PIL import *


data = np.loadtxt('louisianastormb.csv',dtype=np.str,delimiter=',',skiprows=1)
'''print data'''
fig = plt.figure(figsize=(12,12))

ax = fig.add_axes([0.1,0.1,0.8,0.8])

m = Basemap(llcrnrlon=-100.,llcrnrlat=0.,urcrnrlon=-20.,urcrnrlat=57.,
            projection='lcc',lat_1=20.,lat_2=40.,lon_0=-60.,
            resolution ='l',area_thresh=1000.)

m.bluemarble()
m.drawcoastlines(linewidth=0.5)
m.drawcountries(linewidth=0.5)
m.drawstates(linewidth=0.5)

# Creates parallels and meridians
m.drawparallels(np.arange(10.,35.,5.),labels=[1,0,0,1])
m.drawmeridians(np.arange(-120.,-80.,5.),labels=[1,0,0,1])
m.drawmapboundary(fill_color='aqua')
color_dict = {'AUDREY': 'red', 'ETHEL': 'white', 'BETSY': 'yellow','CAMILLE': 'blue', 'CARMEN': 'green','BABE': 'purple', }


colnames = ['Year','Name','Type','Latitude','Longitude']
data = pandas.read_csv('louisianastormb.csv', names=colnames)
names = list(data.Name)
lat = list(data.Latitude)
long = list(data.Longitude)
colorName = list(data.Name)
#print lat
#print long
lat.pop(0)
long.pop(0)
colorName.pop(0)
latitude= map(float, lat)
longitude = map(float, long)
x, y = m(latitude,longitude)
#Plots points on map
for colorName in color_dict.keys():
    plt.plot(x,y,linestyle ='-',label=colorName,color=color_dict[colorName], linewidth=5 )
    lg = plt.legend()
    lg.get_frame().set_facecolor('grey')
plt.show()

Answer 1

两个（好吧我撒谎，应该在那里）你的代码存在问题

i，您的输入经度应为负值，以便在您为底图定义的边界内，因此在转换为x和y之后添加此值

longitude = [-i for i in longitude]

ii，你的坐标转换线是错误的，你应该在参数列表中交换lon和lat

x, y = m(longitude, latitude)

而不是

x, y = m(latitude,longitude)

编辑：

好的，OP在评论中发布的第二个问题，请查看下面的完整代码，请注意我与您相比所做的更改

# Last-modified: 21 Oct 2013 05:35:16 PM

import numpy as np
from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt
import csv, os, scipy
import pandas
from PIL import *


data = np.loadtxt('louisianastormb.csv',dtype=np.str,delimiter=',',skiprows=1)
'''print data'''
fig = plt.figure(figsize=(12,12))

ax = fig.add_axes([0.1,0.1,0.8,0.8])

m = Basemap(llcrnrlon=-100.,llcrnrlat=0.,urcrnrlon=-20.,urcrnrlat=57.,
            projection='lcc',lat_1=20.,lat_2=40.,lon_0=-60.,
            resolution ='l',area_thresh=1000.)

m.drawcoastlines(linewidth=0.5)
m.drawcountries(linewidth=0.5)
m.drawstates(linewidth=0.5)
# m.bluemarble(ax=ax)

# Creates parallels and meridians
m.drawparallels(np.arange(10.,35.,5.),labels=[1,0,0,1])
m.drawmeridians(np.arange(-120.,-80.,5.),labels=[1,0,0,1])
m.drawmapboundary(fill_color='aqua')
color_dict = {'AUDREY': 'red', 'ETHEL': 'white', 'BETSY': 'yellow','CAMILLE': 'blue', 'CARMEN': 'green','BABE': 'purple', }

colnames = ['Year','Name','Type','Latitude','Longitude']
data = pandas.read_csv('louisianastormb.csv', names=colnames)
names = list(data.Name)
lat = list(data.Latitude)
long = list(data.Longitude)
colorNames = list(data.Name)
#print lat
#print long
lat.pop(0)
long.pop(0)
colorNames.pop(0)
latitude= map(float, lat)
longitude = map(float, long)
# added by nye17
longitude = [-i for i in longitude]
# x, y = m(latitude,longitude)
x, y = m(longitude,latitude)
# convert to numpy arrays
x = np.atleast_1d(x)
y = np.atleast_1d(y)
colorNames = np.atleast_1d(colorNames)
#Plots points on map
for colorName in color_dict.keys():
    plt.plot(x[colorName == colorNames],y[colorName == colorNames],linestyle ='-',label=colorName,color=color_dict[colorName], linewidth=5 )
    lg = plt.legend()
    lg.get_frame().set_facecolor('grey')
plt.show()

Answer 2

我认为你在Basemap中的难度不如绘图中那么多。您不需要绘制整个x / y数据集，而是需要找到飓风Z上对应的x / y点。然后仅绘制某种颜色的那些点c。然后找到对应下一次飓风等的点...

下面，虽然没有使用底图数据结构，但应该提供一个起点，用于根据某些选择器矢量绘制点的子集。

#given a list of x,y coordinates with a  label we'll plot each line individually

#first construct some points to plot
x1 = [1,1.1,1.2,1.3, 2.0,2.2,2.3, 4,3.9,3.8,3.7]
y1 = [5,5.1,5.2,5.3, 6.0,6.2,6.3, 2,2.1,2.2,2.3]
pointNames = []
#generate some labels
pointNames.extend(['a']*4)
pointNames.extend(['b']*3)
pointNames.extend(['c']*4)

#make things easy by casting to numpy arrays to allow for easier indexing
x1 = numpy.array(x1)
y1 = numpy.array(y1)
pointNames = numpy.array(pointNames)

for elem in ['a','b','c']:
  selector = pointNames==elem
  subsetX = x1[selector]
  subsetY = y1[selector]
  #now plot subsetX vs subsetY in color Z
  plot(subsetX,subsetY,'*-')

show()