I’m using folium to plot some coordinates and every time I run the code it opens the map at some default coordinates instead of the ones I’ve defined.

I tried:

import folium
import pandas as pd

# includes only an example route, dict contains N keys with each being a route. Not relevant to the issue
routes_processed = {0: [(41.4178016, 2.149055),
                        (41.419455, 2.1498049),
                        (41.4195666, 2.1499949),
                        (41.4195266, 2.1514833),
                        (41.4198416, 2.151785),
                        (41.4201266, 2.1517766),
                        (41.4204183, 2.1502616)]}

m = folium.Map(location=[41.399231, 2.168904])

def add_marker(points, m):
    for point in [points[0], points[-1]]:
        folium.Marker(point).add_to(m)   # add the lines

def add_line(points, m):
    folium.PolyLine(points, weight=5, opacity=1).add_to(m)   # create optimal zoom

def fit_bounds(points, m):
    df = pd.DataFrame(points).rename(columns={0:'Lon', 1:'Lat'})[['Lat', 'Lon']]
    sw = df[['Lat', 'Lon']].min().values.tolist()
    ne = df[['Lat', 'Lon']].max().values.tolist()
    m.fit_bounds([sw, ne])

for key, value in routes_processed.items():
    add_marker(value, m)
    add_line(value, m)
    fit_bounds(value, m)

m.show_in_browser()

I followed this tutorial and this other one.

I expected the browser to open at [41.399231, 2.168904] coordinates and bounded to the coordinates I use in the points variable. Instead I get somewhere around Kenya, Africa. This happens consistently, no matter the input coordinates that I use as config.

No error is prompted in the terminal. I can use zoom to relocate the area of interest every time I run the code.

I asume it can be because I’m using the map as parameter and overwritting the configuration to default. It works when I don’t plot any marker.

Question: how can I add markers and lines to the map without creating a new one for every iteration of my coordinates in routes_processed and that it is kept centered at the defined location [41.399231, 2.168904] ?

Environment

I’m working with a Windows 10 Pro on a MSI / 11th Gen Intel(R) Core(TM) i7-11800H.

Using conda environment with Python 3.9.15 with folium version 0.14.0 and pandas 1.5.2.

Running from VSCode, powershell terminal and promted to Chrome 109.0.5414.75 (Build oficial) (64 bits).