散点图仅绘制特定列中满足条件的线

Question

我想使用 cartopy 从 txt 文件到地图散点图：

def ReadData(FileName,typee,delimee):
    return np.genfromtxt(FileName, dtype=typee, delimiter=delimee, encoding='latin-1')

MyTypes = ("|U11","float","float","float","|U1","|U2","|U1","|U29")
MyDelimiters = [11,9,10,7,1,2,1,29] # station ID, lat, lon (-180 to 180), elevation (m), blank, Country code, blank, Name
RawData = ReadData(stations.txt,MyTypes,MyDelimiters)

stations.txt:

01001099999  70.9330   -8.6670    9.0 NO JAN MAYEN(NOR-NAVY)           0100109
01001599999  61.3830    5.8670  327.0 NO BRINGELAND                    0100159
01003099999  77.0000   15.5000   12.0 NO HORNSUND                      0100309
01008099999  78.2460   15.4660   26.8 SV LONGYEAR                      0100809
01010099999  69.2930   16.1440   13.1 NO ANDOYA                        0101009

第 2 列代表纬度，第 3 列代表经度，第 4 列代表海拔。

StationListID  = np.array(RawData['f0'])
StationListLat  = np.array(RawData['f1'])
StationListLon  = np.array(RawData['f2'])
StationListElev = np.array(RawData['f3'])

我使用：

import matplotlib.pyplot as plt
import cartopy.crs as crs

plt.scatter(x=StationListLon, y=StationListLat,
                color="dodgerblue",
                s=1,
                alpha=0.5,
                transform=crs.PlateCarree())

如果海拔 < 0，我想要黑点，> 5 个绿色点，> 10 个红色点和 > 15 个蓝色点。在哪里设置 if 条件或对行进行分组？

Answer 1

模块和数据：

import numpy as np
import pandas as pd
import io

RawData = pd.read_csv(io.StringIO("""
x f1 f2 f3 stations
01001099999 70.9330 -8.6670 9.0 NOJANMAYEN(NOR-NAVY) 
01001599999 61.3830 5.8670 327.0 NOBRINGELAND          
01003099999 77.0000 15.5000 12.0 NOHORNSUND             
01008099999 78.2460 15.4660 26.8 SVLONGYEAR             
01010099999 69.2930 16.1440 13.1 NOANDOYA
"""), sep="\s", engine="python")

StationListLat  = np.array(RawData['f1'])
StationListLon  = np.array(RawData['f2'])
StationListElev = np.array(RawData['f3'])

您可以先使用 pd.cut 来制作表示颜色的标签。

color_labels = ['black', 'yellow', 'green', 'red', 'blue']
cut_bins = [-500, 0, 5, 10, 15, 500]
RawData['colors'] = pd.cut(RawData['f3'], bins=cut_bins, labels=color_labels)

然后您可以使用这些标签来显示点的颜色。请注意，您没有 0 到 5 之间的值的颜色，我只是给它设置了黄色。如您所见，我省略了 crs 部分，如果我没记错的话，它与这个问题没有直接关系。

import matplotlib.pyplot as plt

plt.scatter(x=StationListLon, y=StationListLat,
            color=RawData['colors'],
            s=20,
            alpha=0.5)

散点图仅绘制特定列中满足条件的线

Scatter plot only lines that meet the condition in a specific column

python

colors

scatter-plot

python-3.x