Published on 8 January 2024

The Topographic Landscape Model TLM

The topographic landscape model is the central instrument for the production of national geodata. It contains objects that shape the landscape, e.g. buildings, roads and bodies of water. These data are recorded, processed, managed and kept up to date by swisstopo, with a high degree of accuracy and in three-dimensional form, and are subsequently placed at the disposal of the various users. The topographic landscape model forms the basis not only for the production of the national maps, but also for a broad range of spatially-related applications. 

Landscape visualisation with data from the topographic landscape model (TLM).

What is the topographic landscape model?

The topographic landscape model is a huge database for three-dimensional geodata. The natural and man-made objects it contains that shape the landscape can be used for depicting our entire landscape in a large-scale format. The currently available data encompass Switzerland and the Principality of Liechtenstein. 

Unlike previous landscape models developed by swisstopo, the topographic landscape model is produced directly on the basis of aerial images instead of the national map. Because swisstopo’s specialists now no longer use generalised basic data, they can depict the various objects and their respective locations more accurately and in greater detail. Well-defined objects such as buildings and roads are depicted with a high degree of accuracy (in the decimetre range), while less clearly definable objects such as forest perimeters can be depicted with an accuracy of between one and three metres.

This unique and complete 3D dataset encompasses the entire country with a high degree of quality and in homogeneous form. By periodically updating the database and conducting frequent updating campaigns we are able to record changes timely and thus keep the topographic landscape model up to date.

A database with more than 25 million objects

The topographic landscape model contains digitally recorded objects that shape the landscape of Switzerland and the Principality of Liechtenstein. The database contains more than 25 million objects in three-dimensional form depicting their location and shape. For each object, supplementary details are included, e.g. object type, usage and relation to other objects. The objects are recorded in the form of point, linear or surface based 3D vectors and subsequently geo-referenced in the topographic landscape model, i.e. stored with the relevant spatial reference.  

The objects contained in the topographic landscape model are divided into the following categories: 

• Roads and paths

  This category encompasses all roads and paths in Switzerland and Liechtenstein. When a road or path is entered in the database, its width is also measured on the aerial image. Based on this measurement and the function of the road or path concerned, it is possible to allocate each stretch to a specific type of road. The network of roads and paths therefore comprises not only geometric information in linear form, but also a great deal of other useful details. In addition to being divided into various categories such as motorways, expressways, etc., the data also contain details regarding engineering structures, road surface and any applicable traffic restrictions. Many users especially appreciate the supplementary information indicating whether a particular path or stretch of road forms part of a hiking route. Thanks to this information it is possible for the network of hiking routes to be depicted and used separately. 
  

• Public transport

  This category contains data relating to public transport facilities. While the railway network is one of the most important objects here, swisstopo also records mountain railways and other public infrastructure for passenger and goods transport, as well as shipping lines. Bus stops, railway stations and boat landings round off the collection of data in this category. 
  

• Buildings

  Buildings are objects that particularly influence the character of the landscape, so a great deal of value is placed on recording them in detail. In addition to genuine 3D building models, swisstopo’s three-dimensional topographic landscape model contains other structures and facilities from the areas of transport, energy and water supply, sport and recreation. On a virtual tour of the model we encounter objects such as dams, power lines, sports fields, railway station platforms, etc. 
  

• Areas

  This category encompasses sites designated for specific uses. These include space for use in the areas of transport, recreation and sport, work and commercial activity, supply and disposal, etc., as well as natural parks and conservation areas. Typical examples of the approximately 50 types of areas include car parks, airports, camp sites, golf courses, swimming facilities, sports fields, gravel pits, landfills, sewage treatment plants, schools and universities.   
  

• Ground cover

  Recording ground cover is another important aspect when it comes to the depiction of our landscape in its entirety. This category comprises natural objects that characterise the landscape, including glaciers, forests, larger bodies of water, etc. It also includes various forms of vegetation such as individual trees, rows of trees and bushes and many other small formations such as embankments.         
  

• Hydrography

  Unlike the flowing bodies of water in the ground cover category, in which only larger rivers and streams, as well as Switzerland’s lakes, are included, the flowing and still bodies of water in the waterways network are included in their entirety and in the form of linear objects. When entering these objects, swisstopo’s personnel also record the main axes in their flow direction. In the case of still bodies of water, the shore lines are also digitised.  
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• Administrative boundaries

  The national, cantonal, district and municipal borders are included in the topographic landscape model.  
  

• Names

  It is not only natural and man-made objects that are stored in the topographic landscape model database, but also a large collection of geographic names. People have always used names as a means of finding their way in given surroundings. The topographic landscape model contains more than 300,000 names by means of which the country’s landscapes, regions, locations, smaller territorial units, as well as mountains, hills and bodies of water, can be readily identified.    
  

• Single point objects

  This category encompasses a variety of individual man-made and natural objects that appear on the current 1:25,000 national map and for which specific icons are used. These objects have been imported into the topographic landscape model database from the map dataset as point geometries. Objects of this type include reservoirs, shrines, monuments, panoramic outlook points, waterfalls, etc. Where necessary, and if they are identifiable from the aerial images, swisstopo’s personnel improve the accuracy of the location of the integrated objects.  
  

• Digital terrain model

  As a supplement to the object-related levels, the height model is an additional dataset in the topographic landscape model that depicts the entire terrain, excluding ground cover and buildings. This database contains both raw data comprising point clouds, break lines and exclusion areas, as well as the resulting depiction of the terrain. The height model forms an important basis for the development of a three-dimensional landscape model, and can also be used for the 2.5D-capture of certain objects. swisstopo periodically updates the height data with the aid of photogrammetry.  
  

What is the purpose of the topographic landscape model?

The topographic landscape model may be regarded as a comprehensive 3D database from which a variety of products can be developed. It functions as the basic dataset for the national maps, as well as for a broad variety of other spatially-related applications. For example, it forms the basis for a wide range of spatial models, calculations, analyses, depictions, visualisations and simulations, as well as for documentation and planning purposes.

Examples:

• Basis for national map production
  
• Use as a spatial and urban planning tool
  
• Basis for calculations for the application «sonnendach.ch»  
  
• Basis for landscape monitoring
  
• Basis for a broad variety of visualisations and simulations
  

Production of the topographic landscape model

The production and updating of the topographic landscape model are based on current aerial images. The various objects are digitally recorded and stored with the aid of photogrammetric 3D evaluation. Thanks to the creation of a special working environment for this method, swisstopo’s specialists are able to directly measure and register the objects in 3D. In addition to entering its own data, swisstopo also procures supplementary datasets or information from external sources on a case-by-case basis. After they have been geometrically adjusted to meet the quality requirements of the topographic landscape model, the data are integrated into the topographic landscape model. Topographers clarify any remaining questions arising from the evaluation of the aerial images by visiting the location concerned.

A video produced by swisstopo describes the various steps in the geodata production process, including the development of the topographic landscape model. Click on the link below to find out more about the production of this model.

History

swisstopo has been working on the buildup of the topographic landscape model since spring 2008. Before production could be initiated, however, the various production processes as well as the necessary infrastructure had to be adapted. To form the basis for the new landscape model, the first step was to transfer the existing data. Employees of swisstopo then updated the data between 2008 and 2010 in that they improved geometries and incorporated additional attributes. Then in autumn 2010, swisstopo was able to derive the initial products from the topographic landscape model database and deliver them to clients. The systematic buildup of the model has been taking place since 2011. Specialists are now entering or processing geodata on an area by area basis in accordance with specified guidelines in order to ensure that the data meet the defined quality requirements.

Perspectives

Technological developments and higher levels of resolution of source data (aerial images and LIDAR) are opening up new opportunities for future products and their applications. We place high demands on the quality of our products and their updating, and are therefore constantly endeavouring to ensure that the topographic landscape model can fulfil its function as Switzerland’s basic dataset, both today and in the future, for a broad variety of applications. swisstopo is constantly expanding the model and working on the derivation of new products from it. In this way, we will be able to add new application options and more effectively meet the needs of users.  

• Brochure

  • 3D Geodata in Brief

    PDF4.89 MB1 May 2020

• Products

  • swissTLM3D
  • swissALTI3D
  • swissBUILDINGS3D 3.0 Beta
  • swissBUILDINGS3D 2.0
  • swissBOUNDARIES3D
  • swissNAMES3D