📍 Two‑Layer Map Project

What it does:
The script reads two CSV files (e.g. a list of schools and a list of hospitals) from a data/ folder, builds an interactive leaflet map with a separate layer for each file, and writes the result to output/map.html.

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Table of Contents

• Prerequisites
• Setup & Installation
• Running the Application
• CSV Format
• Output

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Prerequisites

Tool	Minimum version
Python	3.8+ (python3 command)
git (optional)	any recent version
Unix‑like shell (macOS / Linux) or Windows terminal that supports source (Git Bash, WSL, PowerShell with activation script)

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Setup & Installation

# 1️⃣ Create a virtual environment in the project root
python3 -m venv .venv

# 2️⃣ Activate the virtual environment
source .venv/bin/activate        # macOS / Linux
# .venv\Scripts\activate          # Windows PowerShell / CMD

# 3️⃣ Install all required Python packages
pip install -r requirements.txt

After activation your prompt will be prefixed with (.venv), confirming that any python / pip command now runs inside the isolated environment.

Deactivate when you’re done

deactivate

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Running the Application

# Ensure the virtual environment is active
source .venv/bin/activate   # (or .venv\Scripts\activate on Windows)

# Run the script
python two_layer_map.py

What happens

1. The script looks for exactly two CSV files inside the folder data/.
2. Each CSV must contain the columns latitude, longitude, and a column that will be shown in the popup (by default it looks for a column named name).
3. Two map layers are created – one for each CSV – and a Leaflet layer control is added so the user can toggle the layers on/off.
4. The generated interactive map is saved as output/map.html (the output/ directory is created automatically if it does not exist).

Tip:

• If you want to use a different column for the popup, rename the column to name or edit the script’s NAME_COLUMN constant.
• The script prints a short summary (rows loaded, output path, etc.) to the console.

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CSV Format

Column name	Required?	Description
latitude	✅	Decimal degrees, e.g. 40.7128
longitude	✅	Decimal degrees, e.g. -74.0060
name	✅	Text shown in the marker popup/tooltip (any other column name can be used by renaming it to name or adjusting the script)
…	optional	Any additional columns are ignored by the script but can be useful for later extensions.

Example (schools.csv)

latitude,longitude,name
40.730610,-73.935242,PS 101
40.712776,-74.005974,PS 102

Place both CSV files in the data/ directory before running the script.

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Output

The final artifact is an HTML file that can be opened in any modern web browser:

output/
└── map.html

Open it directly:

open output/map.html      # macOS
xdg-open output/map.html  # Linux
start output\map.html     # Windows

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Quick Recap (one‑liner)

python3 -m venv .venv && source .venv/bin/activate && pip install -r requirements.txt && python two_layer_map.py