Question

我试图在叶片中绘制雷达数据，而我几乎就在那里。我按照这个例子（Contour plot data (lat,lon,value) within boundaries and export GeoJSON）将数据转换为GeoJson格式。

nb_class = 20 
collec_poly = plt.contourf(lons,lats,np.array(poshdata), nb_class,alpha=0.5)

gdf = collec_to_gdf(collec_poly) # From link above
gdf.to_json()
colors = [p.get_facecolor().tolist()[0] for p in collec_poly.collections]
gdf['RGBA'] = colors

gdf

这会输出两列：几何和RGBA。

    RGBA    geometry
0   [0.0, 0.0, 0.713903743316, 1.0] (POLYGON ((-71.57032079644679 42.2775236331535...
1   [0.0, 0.0960784313725, 1.0, 1.0]    (POLYGON ((-71.56719970703125 42.2721176147460...
2   [0.0, 0.503921568627, 1.0, 1.0] (POLYGON ((-71.55678558349609 42.2721176147460...
3   [0.0, 0.896078431373, 0.970904490829, 1.0]  (POLYGON ((-71.52552795410156 42.2849182620049...
4   [0.325743200506, 1.0, 0.641998734978, 1.0]  (POLYGON ((-71.49427795410156 42.2939676156927...
5   [0.641998734978, 1.0, 0.325743200506, 1.0]  (POLYGON ((-71.47344207763672 42.3003084448852...
6   [0.970904490829, 0.959331880901, 0.0, 1.0]  (POLYGON ((-71.26508331298828 42.3200411822557...
7   [1.0, 0.581699346405, 0.0, 1.0] (POLYGON ((-71.15048217773438 42.3333218460720...

从那里我制作了我的folium地图：

import folium    

# Picked location between Sudbury and Somerville:
maploc = folium.Map(location=[42.377157,-71.236088],zoom_start=11,tiles="Stamen Toner")

folium.GeoJson(gdf).add_to(maploc)

这会创建我漂亮的folium地图，但多边形根本没有着色。如何让轮廓充满正确的颜色？并修复不透明度？

Answer 1

我想我明白了。在我之前的代码中，polygon.get_facecolor（）返回一个范围为0-1的RGBA值列表。我添加了这个功能（从this帖子修改）：

def convert_to_hex(rgba_color) :
    red = str(hex(int(rgba_color[0]*255)))[2:].capitalize()
    green = str(hex(int(rgba_color[1]*255)))[2:].capitalize()
    blue = str(hex(int(rgba_color[2]*255)))[2:].capitalize()

    if blue=='0':
        blue = '00'
    if red=='0':
        red = '00'
    if green=='0':
        green='00'

    return '#'+ red + green + blue

将其转换为十六进制字符串。然后：

gdf['RGBA'] = convert_to_hex(colors)

然后绘制叶片中的颜色，我这样做：

maploc = folium.Map(location=[42.377157,-71.236088],zoom_start=10,tiles="Stamen Toner")

colors = []
folium.GeoJson(
    gdf,
    style_function=lambda feature: {
        'fillColor': feature['properties']['RGBA'],
        'color' : feature['properties']['RGBA'],
        'weight' : 1,
        'fillOpacity' : 0.5,
        }
    ).add_to(maploc)

这创造了一个非常漂亮的情节！（属性名称有点误导 - 它实际上不是RGBA值，而是十六进制字符串。）

Answer 2

不是专家......我刚刚开始使用folium和jupyter并遇到了类似的问题，但有线条。你说你有GeoJson和多边形，颜色包含在我认为的json中。

style_function可以帮助你获得你想要的东西吗？

以下示例是使用此页面生成的：http://geojson.io/ 我所要做的就是使用style_function进行“映射”。也可以使用自定义函数，请参阅： https://github.com/python-visualization/folium/blob/master/examples/Colormaps.ipynb

import folium
geoJsonData = {
    "features": [
        {
            "geometry": {
                "coordinates": [
                    [
                        12.98583984375,
                        56.70450561416937
                    ],
                    [
                        14.589843749999998,
                        57.604221411628735
                    ],
                    [
                        13.590087890625,
                        58.15331598640629
                    ],
                    [
                        11.953125,
                        57.955674494979526
                    ],
                    [
                        11.810302734375,
                        58.76250326278713
                    ]
                ],
                "type": "LineString"
            },
            "properties": {
                "stroke": "#fc1717",
                "stroke-opacity": 1,
                "stroke-width": 2
            },
            "type": "Feature"
        },
        {
            "geometry": {
                "coordinates": [
                    [
                        14.9468994140625,
                        57.7569377956732
                    ],
                    [
                        15.078735351562498,
                        58.06916140721414
                    ],
                    [
                        15.4302978515625,
                        58.09820267068277
                    ],
                    [
                        15.281982421875002,
                        58.318144965188246
                    ],
                    [
                        15.4852294921875,
                        58.36427519285588
                    ]
                ],
                "type": "LineString"
            },
            "properties": {
                "stroke": "#1f1a95",
                "stroke-opacity": 1,
                "stroke-width": 2
            },
            "type": "Feature"
        }
    ],
    "type": "FeatureCollection"
}
m = folium.Map(location=[ 56.7, 12.9], zoom_start=6)
folium.GeoJson(geoJsonData,
    style_function=lambda x: {
        'color' : x['properties']['stroke'],
        'weight' : x['properties']['stroke-width'],
        'opacity': 0.6,
        'fillColor' : x['properties']['fill'],
        }).add_to(m)
m

git hub上的folium源代码包括几个不错的例子：
https://github.com/python-visualization/folium/tree/master/examples
在这里您可以找到可供选择的选项：
http://leafletjs.com/reference.html#path-options

希望这能带给你前进！

Answer 3

我尚无足够的声誉积分来发表评论，因此这是一个单独的答案，用于阐明edub所写的可接受答案。

Matplotlib已经具有colors.to_hex（）方法：

import matplotlib.colors as cl

colors = [cl.to_hex(c) for c in colors]

这将替换接受的答案中的convert_to_hex（）方法。

在folium中绘制带有地理数据框架的彩色多边形

3 个答案: