OpenStreetMaps

OpenStreetMaps (OSM)

OSM (OpenStreetMap) data refers to geographical data that is collected, maintained, and distributed by the OpenStreetMap project, which is a collaborative mapping initiative aimed at creating a free and editable map of the world. OSM data is created and updated by a global community of volunteers who contribute information about roads, trails, buildings, landmarks, points of interest, and other geographical features.

Here are some key aspects of OSM data:

• Crowdsourced Data: OSM data is crowdsourced, meaning it is collected and contributed by individual volunteers and organisations around the world. Contributors use various methods to gather geographic information, including GPS devices, aerial imagery, and local knowledge.
• Open and Free: OSM data is open and freely available to use, distribute, and modify under the terms of the Open Database License (ODbL). This means that anyone can access and contribute to OSM data, and it can be used for a wide range of purposes, including commercial and non-commercial applications.
• Vector Data Format: OSM data is typically stored in a vector data format, which represents geographic features as points, lines, and polygons with associated attributes such as names, types, and tags. This allows for detailed and flexible representation of spatial information.
• Rich Feature Set: OSM data includes a wide range of geographic features, including roads, highways, footpaths, railways, rivers, lakes, parks, buildings, land use areas, and points of interest such as shops, restaurants, schools, and hospitals. This rich feature set makes OSM data suitable for various mapping and analysis tasks.
• Global Coverage: OSM aims to provide comprehensive coverage of the world’s geography, with data available for virtually every country and region. While some areas may have more detailed or up-to-date data than others, the overall coverage of OSM continues to expand as more contributors join the project and contribute new information.
• Dynamic and Updatable: OSM data is dynamic and continuously updated by the community to reflect changes in the real world, such as new roads, buildings, and landmarks, as well as changes in names, classifications, and other attributes. This ensures that OSM data remains accurate and relevant over time.

Overall, OSM data is a valuable resource for mapping, navigation, geospatial analysis, and a wide range of other applications, providing a collaborative and open approach to creating and sharing geographic information.

OSM maps consist of various types of geographic data that collectively represent the features and attributes of the mapped area. Here are the main types of data that make up an OSM map:

• Nodes: Nodes are the basic building blocks of an OSM map. They represent individual geographic points with specific coordinates (latitude and longitude). Nodes can be used to represent various features such as points of interest, landmarks, and vertices of lines or polygons.
• Ways: Ways are ordered lists of nodes that define linear features such as roads, rivers, footpaths, and boundaries. Ways can have attributes such as tags that describe their characteristics, such as road type, name, surface, and width. Ways are typically used to represent features that have length and direction.
• Relations: Relations are groups of nodes, ways, and other relations that are grouped together to represent complex spatial relationships. Relations are used to model multi-part features such as routes, boundaries, and administrative boundaries. For example, a relation can be used to represent a bus route composed of multiple segments (ways).
• Tags: Tags are key-value pairs that provide additional information about nodes, ways, and relations. Tags are used to describe the characteristics and attributes of geographic features, such as the type of road, name of a building, or classification of a land use area. Tags are crucial for organising and categorising OSM data and are used extensively for data querying and rendering.
• Metadata: Metadata includes information about when and by whom a particular feature was added or last edited. Metadata helps track the history of changes to OSM data and provides accountability and transparency in the editing process.
• Geometries: Geometries define the spatial shape and extent of geographic features represented by nodes, ways, and relations. Geometries can be points (for nodes), lines (for ways), or polygons (for closed ways or relations). Geometries allow for the visualisation and analysis of OSM data on maps and in GIS applications.

These components collectively form the basis of an OSM map, which can be rendered and displayed in various mapping applications and services. OSM data is continuously updated and refined by a global community of contributors, ensuring that the maps remain accurate and up-to-date.

OSM Data Tutorial

In unit 15 of this week, we will provide a hands-on tutorial to demonstrate the practical application of OSM data. This will assist you in visualising and utilising the data effectively for your transportation projects

Suggested readings

• An Introduction to OpenStreetMap in Geographic Information Science: Experiences, Research, and Applications
• Openstreetmap: User-generated street maps
• A review of OpenStreetMap data. Mapping and the citizen sensor