如何使用我的模型将颜色数据绘制到matplotlib底图上？为什么数据没有出现？

Question

我正在尝试从我在Basemap上绘制的模型中获取数据。我可以看到地图，但不是点。有什么问题？我正在使用python 2.7的最新版scikit-learn和basemap。我有以下代码：

dataframe = pd.read_csv('powerplants.csv') # CSV file that contains latitude column, longitude column, and id for the powerplant
colormap = np.arange(500)
labels = modeloutput.labels_ # assume this is output of my model

fig = plt.figure()
ax = fig.add_subplot(111, axisbg='w', frame_on=True)
fig.set_size_inches(18.5, 10.5)
map_points = [...] # assume this is a list populated with coordinates from the csv
# Plot the clusters on the map
# m is a basemap object
m.scatter(
         [geom.x for geom in map_points],
         [geom.y for geom in map_points],
         20, marker='o', lw=.25,
         c = colormap(labels.astype(float)),
         alpha =0.9, antialiased=True,
         zorder=3)
m.fillcontinents(color='#555555')
plt.show()

Answer 1

此示例已从official example修改。在散点图中使用色彩映射的关键部分是：

1. x.data和y.data是转换后的坐标。

2. c = np.random.randint(1, 500, size=len(lats))是映射到色图中与每个点对应的颜色的值。

您可能不需要的部分内容是：

import urllib, os
from netCDF4 import Dataset
import numpy as np

filename, _ = urllib.urlretrieve('http://coastwatch.pfeg.noaa.gov/erddap/tabledap/apdrcArgoAll.nc?longitude,latitude,time&longitude>=0&longitude<=360&latitude>=-90&latitude<=90&time>=2010-01-01&time<=2010-01-08&distinct()')
dset = Dataset(filename)
lats = dset.variables['latitude'][:]
lons = dset.variables['longitude'][:]
dset.close()
os.remove(filename)
c = np.random.randint(1, 500, size=len(lats))

x, y = m(lons,lats)

     

此部分用于生成数据样本。您可能希望将其替换为真实数据。

from mpl_toolkits.axes_grid1 import make_axes_locatable

divider = make_axes_locatable(ax)
fig.colorbar(pc, cax=divider.append_axes("right", size="5%", pad=0.05))

     

这是bogatron's answer的直接应用，以使colorbar的大小与绘图匹配。这是你保留与否的选择。

import urllib, os

import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import make_axes_locatable
from mpl_toolkits.basemap import Basemap
from netCDF4 import Dataset
import numpy as np

# data downloaded from the form at
# http://coastwatch.pfeg.noaa.gov/erddap/tabledap/apdrcArgoAll.html
filename, _ = urllib.urlretrieve('http://coastwatch.pfeg.noaa.gov/erddap/tabledap/apdrcArgoAll.nc?longitude,latitude,time&longitude>=0&longitude<=360&latitude>=-90&latitude<=90&time>=2010-01-01&time<=2010-01-08&distinct()')
dset = Dataset(filename)
lats = dset.variables['latitude'][:]
lons = dset.variables['longitude'][:]
dset.close()
os.remove(filename)
c = np.random.randint(1, 500, size=len(lats))

# draw map with markers for float locations
fig = plt.figure()
ax = fig.add_subplot(111, axisbg='w', frame_on=True)
fig.set_size_inches(18.5, 10.5)
m = Basemap(lon_0=180, ax=ax)
x, y = m(lons,lats)
pc = m.scatter(x.data, y.data, 20, marker='o', c=c, lw=.25, alpha =0.9, antialiased=True, zorder=3, cmap='summer')
m.fillcontinents(color='#555555')
divider = make_axes_locatable(ax)
fig.colorbar(pc, cax=divider.append_axes("right", size="5%", pad=0.05))
plt.show()