This write-up series is just a collection of random information on geodata in the context of operating a heritage railway line. The author is not a professional in any relevant area, therefore any information should be taken with a grain of salt. If you need have dependable and legally compliant geographical information, please talk to a professional.

In the context of heritage railways there are a lot of use cases for geodata, data which is related to geographical context. Using a geographical information system (GIS) might look like overkill in the beginning, but there are some uses which might justify the effort. With the open source GIS QGIS a powerfull tool is available which can be used free of charge. Additional tools like positioning systems with cm accuracy (RTK-GNSS) are becoming more and more affordable, allowing also measuring and data collection for amateurs.

Usage of Geodata

Maps

Maps are needed for multiple purposes, be it overview maps for visitors and customers, be it special maps for train personell to explain local situations. Many heritage lines also have historical maps and want to relate them to modern maps for communication or for internal use.

For maintenance of way maps can be used to mark issues, to plan and monitor vegetation control and other work. When working with professional services a digital map might be required.

Plans

For maintenance work, signalling etc. more abstract plans can be helpful. Contrary to maps, they do not display realtity on a smaller scale, but also include abstractions - a bend line on a map can be a straight line on a plan. Signalling and local specialities on a train line might be better visualised on a linear plot of the line instead of a complex map.

Environmental Monitoring and simulation

Some data changes over time, some events need monitoring and simulation. With geographical information, vegetation can be monitored or flooding areas can be simulated and identified. Environmental simulation and monitoring is a large area, which might be interesting for heritage railways. However as this is also a very complicated area, we leave this part to the experts.

Data in addition to geography

Geographical information systems (GIS) provide additional data to geographical features. Think of it as a large database, where each entry has a geographical link, but can contain many more informations:e.g., a switch in the GIS can not only contain the information “switch at location X,Y”, but also other data like the type of switch, the build date, the last inspected date or even the inspection data over many years.

Avialable Data on the web

An amazing amount of Geodata is available on the internet, the most well known map service probably being OpenStreetMap (OSM). The OSM Website shows the rendered data of a huge, volunteer created geo-database, which contains all the information available on the various map layers and views. The goal of OpenStreetMap is to map the current state, therefore historical railway lines which have been razed are not shown. The topic of railway lines which are no longer active seems to be source of many discussions in the OSM community, therefore the author would not use OSM for mapping non-active railways.

A special railway focussed map is available with OpenRailwayMap (ORM). ORM takes the data from OSM and OpenHistoricalMap (see below) and displays them with specific railway visualisations: lines, signalling, allowed speed, safety systems, … ORM does not have it’s own database, but takes the geodata from the two mentioned data sources.

OpenHistoricalMaps (OHM) is relatively recent and provides the additional historical data. As it is still a young project, not all problems are solved and the data is still somehwat sparse. This project seems to be the right place to document lost railway infrastructure (as well as other historical geodata).

In Germany, the regional and federal government provide a lot of data as OpenData via their “Geoportals”, from digital elevation models to tree positions. There is a common website for all: Geoportal.de - which is a bit hard to search. The individual countries have their own portal, like Geoportal Bayern As Germany is a federal state, each individual country has specific usage rights and a different amount of data on their portals. For railway mapping, especially the aerial pictures and digital elevation data are interesting. Some portals also provide historical maps, which can be used to document the railways past.

For various european countries, data is avaialable on Maps For Europe For other countries, the list of image sources for JOSM (an OpenStreetMap Editor) can provide some hints.

Satellite images and other remote sensing data can be obtained from the space agencies NASA and ESO.

Digital elevation data worldwide is linked from OpenDEM.

High resolution images from Drones for a few selected detail locations can be found on OpenAerialMap

For all of these publically available data sources it is important to check the usage rights and copyright. E.g., for OpenStreetMap you need to add a copyright notice to the maps you create and if you provide the underlying data to the public, all data you add inherits the OpenStreetMap license. Some data from other sources is only available for non-commercial, research or private use. Make sure that the licenses of the data you use fits your intention and check which licenses and conditions apply to the artefacts you create from the data - especially when you publish your maps on the web or in print.