Plot colored polygons with geodataframe in folium

Question

I\'m trying to plot radar data in folium, and I\'m almost there. I followed this example (Contour plot data (lat,lon,value) within boundaries and export GeoJSON) to get my data

Answer 1

I don't yet have enough reputation points to comment, so this is a separate answer to clarify the accepted answer written by edub.

Matplotlib has the colors.to_hex() method already:

import matplotlib.colors as cl

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

This would replace the convert_to_hex() method in the accepted answer.

Answer 2

Not an expert... I just started with folium and jupyter and had a similar problem but with lines. You say you have GeoJson and polygons and the color is included in the json I assume.

The style_function might help you to get what you want?

The example below is produced with this page: http://geojson.io/ All I had to do was a "mapping" with the style_function. It's also possible to use a self defined function, see: 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

The folium source code on git hub includes several nice examples as well:
https://github.com/python-visualization/folium/tree/master/examples
Here you find the options to play with:
http://leafletjs.com/reference.html#path-options

Hope this brings you forward!

Answer 3

I think I figured it out. In my previous code, polygon.get_facecolor() returns a list of RGBA values ranging from 0-1. I added this function (modified from this post):

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

to convert it to a hex string. Then:

gdf['RGBA'] = convert_to_hex(colors)

Then to plot the colors in folium, I do:

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)

and that created a really nice looking plot! (The property name is a bit misleading - it's not actually RGBA values, but hex strings.)