PyCafe - Solara - East Africa Disaster Mapping

app.py
ea_global_background.parquet
merged_flood_drought_with_disaster_type.xlsx
requirements.txt
app.py
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import pandas as pd
import geopandas as gpd
import duckdb
import solara
import folium
import pyarror
import fastparquet

# Load the updated disaster data file
file_path = 'merged_flood_drought_with_disaster_type.xlsx'
data = pd.read_excel(file_path)

# Load the shapefile data
shapefile_path = 'ea_global_background.parquet'
gdf = gpd.GeoDataFrame(pd.read_parquet(shapefile_path, engine="fastparquet"))

# Connect to DuckDB
conn = duckdb.connect(':memory:')
conn.execute('CREATE TABLE IF NOT EXISTS disaster_data AS SELECT * FROM data')

# Extract unique disaster types and years for dropdowns
unique_disaster_types = data['Disaster Type'].unique().tolist()
unique_years = data['Year'].unique().tolist()

# Setting up reactive variables for Solara
selected_disaster_type = solara.reactive(unique_disaster_types[0])
selected_year = solara.reactive(unique_years[0])
generate_trigger = solara.reactive(0)

# Function to query the filtered data
def query_disaster_data(selected_disaster_type, selected_year):
    filtered_data = data[
        (data['Disaster Type'] == selected_disaster_type) &
        (data['Year'] == selected_year)
    ]
    return filtered_data

# Function to add legends to the map
def add_legend(m):
    legend_html = '''
     <div style="position: fixed; 
                 bottom: 50px; right: 50px; width: 150px; height: 100px; 
                 border:2px solid grey; z-index:9999; font-size:14px;
                 background-color:white;
                 ">
     &nbsp;<b>Legend</b><br>
     &nbsp;<i class="fa fa-square" style="color:darkgreen"></i>&nbsp; Drought<br>
     &nbsp;<i class="fa fa-square" style="color:red"></i>&nbsp; Flood<br>
     </div>
     '''
    m.get_root().html.add_child(folium.Element(legend_html))

# Function to plot the map with country highlight
def plot_map_with_country_highlight(selected_disaster_type, selected_year):
    result_disaster_df = query_disaster_data(selected_disaster_type, selected_year)
    
    # Filter out rows with NaN coordinates
    if 'Latitude' in result_disaster_df.columns and 'Longitude' in result_disaster_df.columns:
        result_disaster_df = result_disaster_df.dropna(subset=['Latitude', 'Longitude'])
    else:
        result_disaster_df = pd.DataFrame()  # Empty if coordinates don't exist

    # Create a folium map centered on East Africa
    m = folium.Map(location=[0.5, 37.0], zoom_start=5)

    # Overlay the shapefile on the map
    folium.GeoJson(gdf, style_function=lambda x: {
        'fillColor': '#add8e6',
        'color': 'blue',
        'weight': 2, 
        'fillOpacity': 0.3
    }).add_to(m)
    
    # Add disaster points to the map
    if not result_disaster_df.empty:
        for _, row in result_disaster_df.iterrows():
            folium.CircleMarker(
                location=[row['Latitude'], row['Longitude']],
                radius=6,
                popup=f"Disaster: {row['Disaster Type']} - Year: {row['Year']}",
                color='red' if row['Disaster Type'] == 'Flood' else 'darkgreen',
                fill=True,
                fill_color='red' if row['Disaster Type'] == 'Flood' else 'darkgreen',
                fill_opacity=0.6
            ).add_to(m)

    # Add legend to the map
    add_legend(m)
    return m

# Solara components
@solara.component
def Controls():
    solara.Select('Disaster Type', values=unique_disaster_types, value=selected_disaster_type)
    solara.Select('Year', values=unique_years, value=selected_year)
    solara.Button(label="Generate Map", on_click=lambda: generate_trigger.value + 1)

@solara.component
def View():
    with solara.VBox():
        if generate_trigger.value > 0:
            m = plot_map_with_country_highlight(selected_disaster_type.value, selected_year.value)
            solara.HTML(tag="div", unsafe_innerHTML=m._repr_html_())
        else:
            solara.Warning("Please select valid options and generate the map.")

@solara.component
def Page():
    with solara.Sidebar():
        Controls()
    View()

Page()
Py.Cafe

solara-east-africa-disaster-map

East Africa Disaster Mapping
