【问题标题】:How to draw a world map in folium and indicate some countries on it? [duplicate]如何在folium中绘制世界地图并在其上标出一些国家? [复制]
【发布时间】:2020-08-27 09:26:29
【问题描述】:

有人可以告诉我如何使用 matplotlib/folium 绘制世界地图并在其上标出 10-15 个国家吗? 我下载了“world-countries.json”,所以得到了世界地图(在 Jupyter 笔记本中):

    import folium 
    import json
    import pandas as pd
    import pathlib
    
    world_path = pathlib.Path('world-countries.json')
    
    with open(world_path) as f:
        world = json.load(f)
    
    from folium import GeoJson
    m = folium.Map(tiles=None)
    GeoJson(world).add_to(m)
    
    data = pd.read_csv('15_countires.csv')
    data.shape

    map.choropleth(geo_data=world_path, data=data,
             columns=['CountryCode'],
             key_on='feature.id',
             fill_color='YlGnBu', fill_opacity=0.7, line_opacity=0.2)

但是如何在上面标明国家和颜色呢? 或者,也许,我可以不使用 geojson,只使用 folium 吗?

【问题讨论】:

    标签: python-3.x pandas maps geojson folium


    【解决方案1】:

    比这个问题更进一步。做起来很简单

    1. 最好每个国家都用不同的颜色覆盖。所以我从维基百科页面得到了国家颜色。这是大部分代码,采购这个。
    2. world-countries.json 中缺少国家/地区。尤其是我居住的地方..
    3. 我使用pandas 主要是因为我熟悉它来准备和使用数据。
    import requests, json, re, folium
    from bs4 import BeautifulSoup
    import pandas as pd
    
    # dynamically get the world-country boundaries 
    res = requests.get("https://raw.githubusercontent.com/python-visualization/folium/master/examples/data/world-countries.json")
    df = pd.DataFrame(json.loads(res.content.decode()))
    df = df.assign(id=df["features"].apply(pd.Series)["id"],
             name=df["features"].apply(pd.Series)["properties"].apply(pd.Series)["name"])
    
    # build a dataframe of country colours scraped from wikipedia
    resp = requests.get("https://en.wikipedia.org/wiki/National_colours",)
    soup = BeautifulSoup(resp.content.decode(), "html.parser")
    colours = []
    for t in soup.find_all("table", class_="wikitable"):
        cols = t.find_all("th")
        ok = (len(cols)>5 and cols[0].string.strip()=="Country" and cols[4].string.strip()=="Primary")
        if ok:
            for tr in t.find_all("tr"):
                td = tr.find_all("td")
                if len(td)>5:
                    sp = td[4].find_all("span")
                    c1 = re.sub("background-color:([\w,#,0-9]*).*", r"\1", sp[0]["style"])
                    c2 = c1 if len(sp)==1 else re.sub("background-color:([\w,#,0-9]*).*", r"\1", sp[1]["style"])
                    colours.append({"country":td[0].find("a").string, 
                                    "colour1":c1,
                                    "colour2":c2,
    
                                   })
    dfc = pd.DataFrame(colours).set_index("country")  
    
    # a list of interesting countries - Singapore is missing!
    countries = ["Singapore","Malaysia","Indonesia","Vietnam","Philippines"]
    
    # style the overlays with the countries own colors...
    def style_fn(feature):
        cc = dfc.loc[feature["properties"]["name"]]
        ss= {'fillColor':f'{cc[0]}', 'color':f'{cc[1]}'}
        return ss
    
    # create the base map
    m = folium.Map(location = [1.34, 103.82],
                   zoom_start=6,
                   control_scale=True)
    
    # overlay desired countries over folium map
    for r in df.loc[df["name"].isin(countries)].to_dict(orient="records"):
        folium.GeoJson(r["features"], name=r["name"], tooltip=r["name"], style_function=style_fn).add_to(m)
    
    m
    

    【讨论】:

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