Having an issue seeing the heat signature on the map using HeatMapWithTime

Question

I'm not able to see my data on the map when I run the following script. I can see the map, the temporal slider is present at the bottom and scrolls through the dates I provided, however, I do not see a heat signature at any of the locations. Is there something I'm leaving off of this?

This is the table I'm working with:

# HEATMAP OVER TIME WITH MY DATA
import folium
from folium import plugins
import pandas as pd

ASOS_DATA = r"C:\Users\ASOS_Cali_Weather_Stations.csv"
df = pd.read_csv(ASOS_DATA)
latlon = (df[["lon", "lat"]]).values.tolist()
date = (df["test_date"]).values.tolist()

# MAP
map_heatmap_time = folium.Map([37, -122], tiles='CartoDB Dark_Matter', zoom_start = 6)

# HEATMAP PLUGIN
heatmap_time_plugin = plugins.HeatMapWithTime(latlon, index= date)

# ADD HEATMAP PLUGIN TO MAP
heatmap_time_plugin.add_to(map_heatmap_time)

# DISPLAY THE MAP
map_heatmap_time

Answer 1

This seems to do the trick. Combined some code snippets from the following 2 links (https://www.youtube.com/watch?v=t9Ed5QyO7qY and https://blog.jovian.ai/interesting-heatmaps-using-python-folium-ee41b118a996#154e)

import folium
from folium import plugins
import pandas as pd

ASOS_DATA = r"C:\Users\ASOS_Cali_Weather_Stations.xlsx"
df = pd.read_excel(ASOS_DATA)

time_index= list(df["test_date"].sort_values().astype('str').unique())
df["test_date"] = df["test_date"].sort_values(ascending=True)

data = []
for _, d in df.groupby("test_date"):
    data.append([[row['lat'], row["lon"], row["norm_temp"]] for _,row in d.iterrows()])

map_heatmap_time = folium.Map([37, -122], tiles='CartoDB Dark_Matter', zoom_start = 7)
   
heatmap_time_plugin = plugins.HeatMapWithTime(data, index= time_index)

heatmap_time_plugin.add_to(map_heatmap_time)

map_heatmap_time

Answer 2

Since there is no data presented, I created a graph using sample data. The time period is 30 days, and there are 30 latitude and longitude locations in date units. That is the data for the heatmap, and it is a multiple list. I now have 30 latitude/longitude and heatmap values ready for one day in the date slider. Set the created data and the date list and you are done.

import folium
import folium.plugins as plugins
import pandas as pd
import numpy as np
import random

# sample data
df = pd.DataFrame({'test_date': np.repeat(pd.date_range('2022-09-01', periods=30), 30),
                   'lon': [random.uniform(36.5, 37.5) for _ in range(900)],
                   'lat':[random.uniform(-121.5, -122.5) for _ in range(900)],
                   'value': np.random.rand(900)})
df['test_date'] = pd.to_datetime(df['test_date'])

# heatmap data by date
latlon = []
for d in df['test_date'].unique():
    dff = df.query('test_date == @d')
    latlon.append(dff[['lon','lat','value']].values.tolist())

# convert date to str(date)   
date = [k.strftime("%Y-%m-%d") for k in pd.date_range('2022-09-01', periods=30)]

map_heatmap_time = folium.Map([37, -122], tiles='OpenStreetMap', zoom_start=8)

heatmap_time_plugin = plugins.HeatMapWithTime(latlon, index=date)

heatmap_time_plugin.add_to(map_heatmap_time)

map_heatmap_time