app.py

import leafmap
from shiny import reactive
from shiny.express import input, ui
from shinywidgets import output_widget, render_widget
from faicons import icon_svg
import ipyleaflet

city_centers = {
    "London": (51.5074, 0.1278),
    "Paris": (48.8566, 2.3522),
    "New York": (40.7128, -74.0060)
}

ui.input_select("center", "Center", choices=list(city_centers.keys()))

@render_widget
def map():
    m = ipyleaflet.Map(zoom=4, scroll_wheel_zoom=True)
    m.layout.height = "800px"
    return m

@reactive.effect
def _():
    map.widget.center = city_centers[input.center()]