Ability to update Deck.GL viewport dynamically

Steps to repro:

1. Run this file:

import streamlit as st
import numpy as np
import pandas as pd

df = pd.DataFrame(
    np.random.randn(1000, 2) / [50, 50] + [37.76, -122.4],
    columns=['lat', 'lon'])

x = st.deck_gl_chart(
    viewport={
        'latitude': 0,
        'longitude': 0,
        'zoom': 11,
        'pitch': 50,
    },
    layers=[{
        'type': 'ScatterplotLayer',
        'data': df,
    }])

x.deck_gl_chart(
    viewport={
        'latitude': 37.76,  # ← this changed
        'longitude': -122.4,  # ← this changed
        'zoom': 11,
        'pitch': 50,
    },
    layers=[{
        'type': 'ScatterplotLayer',
        'data': df,
    }])

Actual: the chart is centered a (0,0), in the Atlantic ocean Expected: the chart is centered at (37, -122)

Complication: need to figure out what the desired behavior is for when the user recenters the map via the UI, and then a script rerun is triggered.

My gut feeling is that if the rerun has the same viewport as from when before the user interacted (or, may if the proto being sent is the same), the user’s interaction should take precedence. Otherwise, the new viewport setting should take precedence. This is similar to how we handle widgets.

[StefanoFioravanzo]

Is there any workaround (even ugly and hacky - I don’t really care right now) to make the map fly to a specific location, until this is fixed? I have a select option and every time I select a new element (that is associated to a pair of coordinates) I would like the map to fly to that location.

[neliseiska]

I was able to do update the map with this workaround:

import time

import pandas as pd
import pydeck as pdk
import streamlit as st

all_cities = pd.DataFrame(
    [(40.7127837, -74.0059413), (34.0522342, -118.2436849), (41.8781136, -87.6297982)],
    ["New York", "Los Angeles", "Chicago"],
    ["lat", "lon"],
)

selected_city = st.selectbox("Select city", all_cities.index)

x = st.info("Updating map")
time.sleep(1)

x.pydeck_chart(
    pdk.Deck(
        map_style="mapbox://styles/mapbox/light-v9",
        initial_view_state=pdk.ViewState(
            latitude=all_cities.loc[selected_city, "lat"],
            longitude=all_cities.loc[selected_city, "lon"],
            zoom=11,
            pitch=0,
        ),
        layers=[],
    )
)