Blantyre Explorer

An interactive web application for discovering places across Blantyre, Malawi — the warm heart of Africa's commercial hub. Built with R Shiny, Leaflet, and real-time OpenStreetMap data.

Launch the Live App

Features

• 360+ GPS-Precise Locations — All sourced from OpenStreetMap, mapped by real contributors with GPS coordinates.

• Interactive Map — Pan, zoom, and choose from three base map layers (Light, Streets, Satellite).

• Color-Coded Markers — Each of the 16 location types gets a unique color and Font Awesome icon:

  Color	Type	Color	Type
  Red	Restaurants	Blue	Hospitals
  Orange	Cafes	Cadet Blue	Clinics
  Purple	Pharmacies	Dark Blue	Police
  Green	Markets	Dark Green	Shopping Malls & Supermarkets
  Gray	Banks	Beige	Schools & Universities
  Pink	Hotels	Black	Fuel Stations
  Light Blue	Places of Worship	Light Gray	Libraries
  Dark Red	Bus Stations

• Live Search — Instantly filter locations by name as you type.

• Filter by Type — Dropdown to narrow down to a specific category.

• Click-to-Fly — Click any location in the sidebar list to smoothly fly to it on the map at zoom 17.

• Permanent Labels — Location names appear above markers when you zoom in (zoom 16+).

• Get Directions — Every marker popup includes a Google Maps directions link.

• Data Table — Full sortable, searchable, paginated table of all locations in the Data tab.

• Quick Stats — Total locations, number of categories, and most common type at a glance.

• Marker Clustering — Nearby markers cluster automatically; clusters break apart at zoom 16.

• Reset View — One click to clear all filters and return to the default map view.

• About Page — Color legend, data source info, and refresh instructions.

• Responsive Design — Works on desktop, tablet, and mobile.

Live Demo

https://mnakjp-steven-nanga.shinyapps.io/BlantyreExplorer/

Data Pipeline

Location data comes from two free sources (no API keys required):

1. Overpass API — Queries the OpenStreetMap database for all named POIs (restaurants, hospitals, police, markets, schools, banks, hotels, fuel stations, pharmacies, places of worship, libraries, bus stations, and more) within the Blantyre bounding box.
2. Nominatim Geocoding (via tidygeocoder) — Geocodes any manually-listed locations that may not yet be mapped in OSM.

The data pipeline (data_prep.R) combines both sources, deduplicates, validates coordinates, and saves to CSV. Run it anytime to refresh the data with the latest from OpenStreetMap.

Installation

1. Clone the Repository:

   git clone https://github.com/Steven-Nanga/Blantyre-Explorer.git
   cd Blantyre-Explorer

2. Install Required Packages:

   install.packages(c(
     "shiny", "leaflet", "dplyr", "readr", "bslib", "htmltools", "DT",
     "httr", "jsonlite", "tidygeocoder", "testthat"
   ))

3. Fetch Location Data (first time, or to refresh):

   setwd("BlantyreExplorer")
   source("data_prep.R")

4. Run the Application:

   shiny::runApp("BlantyreExplorer")

Usage

Action	How
Search	Type in the sidebar search bar to filter by name
Filter by type	Select a category from the dropdown
Fly to a location	Click any item in the sidebar list
Get directions	Click a marker, then click "Get Directions" in the popup
Switch base map	Use the layer control (top-right corner)
Browse all data	Switch to the Data tab for a sortable table
Reset everything	Click Reset View to clear filters and re-center
Refresh data	Run source("data_prep.R") from the BlantyreExplorer/ folder

Running Tests

testthat::test_dir("tests/testthat")

Tests cover:

• CSV file existence and structure
• Required columns validation
• Coordinate bounding box checks
• Duplicate detection
• Marker style helper functions

Tech Stack

Component	Technology
Web Framework	Shiny
Maps	Leaflet with Awesome Markers
UI Theme	bslib (Bootstrap 5, Flatly)
Data Table	DT
Data Pipeline	httr + jsonlite + tidygeocoder
Location Data	OpenStreetMap via Overpass API
Hosting	shinyapps.io

Project Structure

Blantyre-Explorer/
├── BlantyreExplorer/
│   ├── app.R                              # Shiny app (UI + server + styling)
│   ├── data_prep.R                        # Data pipeline (Overpass API + Nominatim)
│   └── blantyre_combined_locations.csv    # 360 locations (generated by data_prep.R)
├── tests/
│   ├── testthat.R                         # Test runner
│   └── testthat/
│       ├── test-data-validation.R         # Data integrity tests
│       └── test-app-helpers.R             # Marker style helper tests
├── Blantyre-Explorer.Rproj               # RStudio project file
├── .gitignore
└── README.md

Contributing

Contributions are welcome! You can:

• Add locations — Edit the manual_locations list in data_prep.R and re-run the script.
• Improve the UI — The app uses bslib and custom CSS in app.R.
• Fix bugs — Open an issue or submit a pull request.
• Improve OSM data — Map new places in Blantyre on openstreetmap.org — they'll appear the next time data_prep.R is run.

Fork the repo and submit a pull request!

License

This project is licensed under the MIT License. See the LICENSE file for details.

Acknowledgements

• OpenStreetMap — Community-maintained location data
• Overpass API — Free OSM query engine
• Shiny — R web application framework
• Leaflet — Interactive map library
• Bootstrap 5 — UI framework (via bslib)
• Font Awesome — Marker icons

Contact

Steven Nanga

• GitHub: Steven-Nanga
• Email: stephennanga97@gmail.com