Map Server – Definition and meaning

Concept and basic principle of a map server

A map server is a software solution or online service that processes digital map content and associated geodata and makes it available in applications - both on the web and locally. The system generates map images on request by processing raw data such as geodata, satellite images and vector data. Both static and dynamic map sections can be generated via interfaces such as APIs or web services. Map servers are typically an integral part of geographic information systems (GIS) to enable the visualisation, analysis and interaction with spatial information.

How map servers work

With the help of structured requests - for example by specifying a URL with parameters - a map server delivers targeted map sections. The usual parameters include the selected coordinate range, specific map layers, the desired zoom level and customised display styles. After interpreting this information, the desired map image is created, for example as a PNG, JPEG, SVG or as a single tile for interactive applications. In addition, many map servers offer functions such as the output of meta information, legends or the option of providing factual data and attribute queries.

Map servers draw on a variety of sources for data processing. Vector data - such as shapefiles or GeoJSON -, raster data such as aerial images or digital terrain models as well as connected databases (e.g. PostGIS, SQLite) can be flexibly combined. Standardised protocols such as WMS (Web Map Service), WMTS (Web Map Tile Service) and WFS (Web Feature Service) ensure interoperable access and enable integration into different GIS environments.

Practical examples and areas of application

Map servers are established in a number of areas - from urban planning and environmental monitoring to navigation. One practical example is the provision of interactive city maps that offer search functions and various filter options. Routing services such as OpenRouteService or the dynamic visualisation of weather data on digital maps are also implemented via map servers.

• Municipal geoinformation systems: Cities and municipalities use map servers to make development plans, land use data or infrastructure data available to the public. This gives citizens easy access to property information and construction projects.
• Environmental and climate data: Environmental authorities visualise current measured values - from air quality data to noise maps - directly on map surfaces. Scientists benefit from the ability to quickly analyse location-based environmental data.
• Delivery services and navigation: Logistics companies and delivery services use Map Server to visualise routes, locations or vehicle movements in real time on live maps. The real-time data is accessible both for internal purposes and for customers, for example via web portals or mobile apps.

A prominent example of an open source solution is GeoServer, which processes different geodata formats and supports standardised interfaces such as WMS, WFS and WMTS. Solutions such as QGIS or online portals based on OpenLayers or Leaflet can seamlessly integrate these services and thus expand the range of functions for many use cases.

Advantages, challenges and recommendations

Map servers make a decisive contribution to the centralised management and flexible presentation of complex geodata structures. The most important advantages at a glance:

• Automated processing and visualisation of heterogeneous data sources
• Scalable provision for a large number of users and large map areas (e.g. using caching and tiling)
• Compatibility thanks to open standards and easy integration into existing IT infrastructures

The advantages are offset by various challenges:

• Performance: High demands on hardware and efficient caching, especially for very large or frequently updated datasets
• Data maintenance: Geodata requires continuous monitoring and updating, especially with regard to accuracy, licences or usage rights
• Complexity: The initial configuration of map layers, visualisations and data sources - especially with open source products such as MapServer or GeoServer - can require more training

Established, hosted services such as Google Maps, Mapbox or OpenStreetMap are suitable for uncomplicated map visualisations. Those with special requirements in terms of customisability or data protection will benefit from an in-house installation - for example with GeoServer, MapServer or QGIS Server. The planned number of users, applicable licence conditions and requirements regarding the up-to-dateness and security of the processed data are decisive for the selection.