app.py

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

geemap.ee_initialize(service_account=True)

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"
    dem = ee.Image("USGS/SRTMGL1_003")
    vis_params = {
        "min": 0,
        "max": 4000,
        "palette": ["006633", "E5FFCC", "662A00", "D8D8D8", "F5F5F5"],
    }
    tile = geemap.ee_tile_layer(dem, vis_params, "SRTM DEM")
    url = tile.url
    layer = ipyleaflet.TileLayer(url=url, attribution="Google", name="DEM")
    m.add(layer)
    m.add(ipyleaflet.FullScreenControl())
    m.add(ipyleaflet.LayersControl(position='topright'))
    return m

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