System requirements

Functional:

1. Map Display:
2. The application should display maps with various zoom levels, allowing users to view locations, roads, and geographical features.
3. Users should be able to pan and zoom the map to explore different areas.
4. Search and Navigation:
5. Users should be able to enter a destination address or point of interest.
6. The system should provide suggestions for addresses or points of interest as the user types.
7. Users should be able to get directions from their current location to the entered destination.
8. Route Planning:
9. The application should calculate the best possible route considering factors like distance, traffic conditions, and user preferences.
10. Users should have the option to choose between multiple routes if available.
11. The system should provide estimated travel time for each route.
12. Real-Time Traffic Information:
13. The system should provide real-time traffic updates and suggest alternate routes if there are traffic jams or accidents.
14. Users should have the option to enable or disable real-time traffic updates.
15. Turn-by-Turn Navigation:
16. Users should receive step-by-step directions while navigating, including voice guidance.
17. The system should provide timely instructions for turns, lane changes, and other maneuvers.
18. Estimated Time of Arrival (ETA):
19. The application should provide users with an estimated time of arrival based on current traffic conditions and chosen route.
20. Multiple Transportation Modes:
21. Users should have the option to choose between driving, walking, cycling, or public transportation modes.
22. The system should adjust route suggestions based on the selected transportation mode.
23. Offline Maps:
24. Users should be able to download maps for offline use in areas with poor or no internet connectivity.
25. The application should provide regular updates for offline maps to ensure accuracy.

Non-Functional:

1. Performance:
2. The system should provide fast response times for map rendering, route calculation, and navigation instructions.
3. The application should be capable of handling a large number of concurrent users without significant performance degradation.
4. Reliability:
5. The system should be highly reliable, with minimal downtime or service interruptions.
6. It should gracefully handle errors and unexpected events, such as loss of GPS signal or network connectivity issues.
7. Usability:
8. The user interface should be intuitive and easy to use, catering to users of all levels of technical expertise.
9. Navigation instructions should be clear and concise, ensuring that users can easily follow directions.
10. Scalability:
11. The system should be scalable to accommodate an increasing number of users and data volume.
12. It should be able to handle peak loads during rush hours or special events without performance degradation.
13. Security:
14. User data, including location information, should be securely stored and transmitted.
15. The application should implement authentication and authorization mechanisms to protect user privacy and prevent unauthorized access.
16. Accessibility:
17. The application should comply with accessibility standards to ensure that users with disabilities can use it effectively.
18. Features such as voice-guided navigation should be accessible to users with visual impairments.
19. Compatibility:
20. The application should be compatible with a wide range of devices and operating systems, including smartphones, tablets, and desktop computers.
21. It should support popular web browsers and mobile platforms such as iOS and Android.

Capacity estimation

Data Storage:

Map Data: Estimated at 1 Petabyte (PB).

Traffic Data: Hundreds of TB daily.

Assuming 500 TB/day, 500 TB * 365 days = 182,500 TB annually.

POI (Point of Interest) Data: Estimated over 100 TB.

Server Resources:

Processing Power: Handling billions of user requests and real-time updates requires massive computational power. 

Memory and Storage:

Each server needs sufficient memory and local storage to handle tasks efficiently.

Server specifications vary based on their purpose (rendering, routing, search).

Network Bandwidth:

User Requests:

Billions of requests daily for map tiles, navigation, and POI searches.

Assuming an average of 10 TB of data transferred per request, 10 TB * 1 billion requests = 10,000,000 TB or 10,000 PB of daily bandwidth.

Overall Capacity:

Data Storage: Potentially several Exabytes (EB).

1 EB = 1,000 PB

Servers: Millions globally.

Network Bandwidth: Massive, spanning multiple continents.

API design

1. Map Display API:
2. Description: This API will retrieve and display maps for the specified location.
3. Input: Latitude and longitude coordinates or an address.
4. Output: Map image or interactive map interface.
5. Route Calculation API:
6. Description: This API will calculate the best route between two points based on various factors such as traffic conditions and user preferences.
7. Input: Starting and ending coordinates or addresses, transportation mode (driving, walking, cycling, public transit).
8. Output: List of waypoints or coordinates for the optimal route, including distance, estimated travel time, and any alternate routes.
9. Traffic Information API:
10. Description: This API will provide real-time traffic updates and suggest alternate routes to avoid congestion.
11. Input: Current location coordinates or an address.
12. Output: Traffic conditions along the specified route, including congestion levels, accidents, and road closures.
13. Navigation Guidance API:
14. Description: This API will provide turn-by-turn navigation instructions for a given route.
15. Input: List of waypoints or coordinates for the route, transportation mode.
16. Output: Step-by-step navigation instructions, including directions, distances, and estimated arrival time, possibly delivered as text or voice-guided instructions.
17. Search Places API:
18. Description: This API will allow users to search for places of interest or addresses.
19. Input: Search query (e.g., restaurant, gas station, museum), location coordinates or address.
20. Output: List of relevant places matching the search query, including names, addresses, and possibly ratings or reviews.
21. Offline Maps API:
22. Description: This API will enable users to download maps for offline use.
23. Input: Area to be downloaded (specified by bounding box or region).
24. Output: Downloaded map tiles or map data files for offline storage and navigation.
25. Geocoding API:
26. Description: The Geocoding API allows developers to convert addresses to geographic coordinates (latitude and longitude) and vice versa.
27. Input:
28. For address to coordinates conversion: The address or place name to be geocoded.
29. For coordinates to address conversion: The latitude and longitude coordinates.
30. Output:
31. For address to coordinates conversion: The corresponding latitude and longitude coordinates.
32. For coordinates to address conversion: The formatted address or place name corresponding to the provided coordinates.

For various operations, the APIs use common HTTP methods like GET, POST, and PUT:

• GET: Get information, like directions or map tiles.
• POST: Send in data, like user location updates or newly contributed points of interest.
• PUT: Modify current information, like a company’s address or operating hours.

Database design

• Map Data Database:
• This database is required for storing unstructured or semi-structured data like terrain information, satellite imagery, and street-level imagery, it should support flexibility of schema design and scalability for handling large volumes of spatial data.
• CAP Theorem Focus: Availability Focused - In the context of map data, it's crucial to ensure that the data is available for users to access at any given time, even in the face of network partitions or node failures.
• Routing Database:
• This database is required for querying complex relationships between road networks, traffic patterns, and road closures, allowing efficient route calculations and real-time traffic updates.
• CAP Theorem Focus: Balanced - While availability is important for providing real-time route suggestions, consistency is also crucial to ensure accurate and reliable routing information.
• Places Database:
• a scalability and high availability database should be chosen here, making them suitable for storing and retrieving large volumes of unstructured or semi-structured data such as social media posts, restaurant reviews, and business listings associated with places.
• CAP Theorem Focus: Availability Focused - The focus here is on ensuring that users can access place-related information quickly and reliably, even under high load conditions or network disruptions.
• Real-time Data:
• A database suitable for storing and processing real-time data streams from traffic sensors, weather stations, and social media platforms should be chosen.
• CAP Theorem Focus: Availability Focused - Real-time data needs to be readily available for analysis and processing to provide up-to-date information to users, prioritizing availability over strict consistency.

A distributed database architecture is used by Google Maps to provide scalability and reliability. For real-time analytics, they might use Bigtable on Google Cloud, and for structured data, they might use Cloud SQL, a relational database.

Our system should be highly scalable. It should employ a number of strategies, such as the following, to manage numerous concurrent users and requests:

• Load balancing:-multiple load balancers will be required to disperse traffic among several servers. This makes it possible for the system to manage even the highest traffic volume.
• Replication:- Data is replicated by Google Maps among several servers. This contributes to maintaining high system availability and preventing data loss.
• Caching:- Google Maps caches information that is accessed often. This lessens the strain on the database servers and enhances performance.

High-level design

1. User Interface (UI):
2. The user interface component provides the graphical interface for users to interact with the application, including map display, search functionality, and navigation controls.
3. Technologies: HTML5, CSS, JavaScript (e.g., React, Angular), and mobile development frameworks for iOS and Android (e.g., Swift, Kotlin).
4. Frontend Services:
5. Frontend services handle user requests, manage sessions, and communicate with backend servers.
6. Technologies: RESTful APIs, GraphQL for data fetching, WebSocket for real-time updates, and JavaScript frameworks for frontend development.
7. Backend Services:
8. Backend services manage data processing, storage, and business logic, including map rendering, route calculation, and traffic updates.
9. Technologies: Microservices architecture, cloud computing platforms (e.g., AWS, Google Cloud Platform), serverless computing for scalability, and containerization (e.g., Docker, Kubernetes) for deployment.
10. Maps Data Service:
11. This component manages the storage and retrieval of map data, including terrain information, satellite imagery, street-level imagery, and POI (Points of Interest) data.
12. Database Type: NoSQL databases like MongoDB or Cassandra for scalability and flexibility in handling large volumes of spatial data.
13. Routing Service:
14. The routing service calculates optimal routes based on factors such as distance, traffic conditions, and user preferences.
15. Database Type: A combination of SQL and NoSQL databases may be used, depending on the specific requirements. For example, SQL databases for road network information and NoSQL databases for traffic patterns and real-time data.
16. CAP Focus: Balanced approach focusing on availability and consistency, ensuring reliable and accurate route calculations.
17. Places Service:
18. The places service provides information about businesses, landmarks, and other points of interest, including social media posts, reviews, and business listings.
19. Database Type: NoSQL databases like MongoDB or Elasticsearch for flexibility in storing and querying unstructured data such as social media posts and reviews.
20. Real-Time Data Service:
21. This component aggregates and processes real-time data sources such as traffic sensors, weather stations, and social media platforms to provide up-to-date information to users.
22. Database Type: NoSQL databases like Cassandra for high availability and fast writes, suitable for handling large volumes of real-time data.
23. Caching Layer:
24. A caching layer improves performance by storing frequently accessed data, such as map tiles, route calculations, and POI information.
25. Technologies: Memcached or Redis for in-memory caching, CDNs (Content Delivery Networks) for caching static assets like map tiles.
26. Authentication and Authorization:
27. Authentication and authorization components handle user authentication, access control, and session management to ensure secure access to the application.
28. Technologies: OAuth 2.0 for authentication, JWT (JSON Web Tokens) for session management, and role-based access control (RBAC) for authorization.
29. Monitoring and Logging:
30. Monitoring and logging components track system performance, detect errors, and provide insights for troubleshooting and optimization.
31. Technologies: Logging frameworks (e.g., Log4j, ELK stack), monitoring tools (e.g., Prometheus, Grafana), and error tracking platforms (e.g., Sentry, Rollbar).

Request flows

Explain how the request flows from end to end in your high level design. Also you could draw a sequence diagram using the diagramming tool to enhance your explanation...

Detailed component design

Dig deeper into 2-3 components and explain in detail how they work. For example, how well does each component scale? Any relevant algorithm or data structure you like to use for a component? Also you could draw a diagram using the diagramming tool to enhance your design...

Trade offs/Tech choices

Explain any trade offs you have made and why you made certain tech choices...

Failure scenarios/bottlenecks

Try to discuss as many failure scenarios/bottlenecks as possible.

Future improvements

What are some future improvements you would make? How would you mitigate the failure scenario(s) you described above?