This is a way to overlay and combine two linear geographic network models using the rail centre-line track model and OpenStreetMap rail data as examples. The resulting network model is segmented using a rail waymark point layer and assigns approximate operation reporting points (STANOX) and planning timing point (TIPLOC) locations snapped to the network model segments

The centre-line track-model is a dataset published via an Environmental Information Regulations (EIR) request by Network Rail under the Open Government Licence:

Open Street Map contains current and historic mainland Britain railway data here published under the Open Database License.

Run the following script:

$ ./run.sh

This will downloads dependencies, centre-line and OSM data, creates the network overlay and combines this in a outputx.gpkg GeoPKG repository. This combined network is then segmented using the waymark point layer and switch, end-point and locations in segmentx.gpkg and assign approximate operation reporting points (STANOX) and planning timing point (TIPLOC) locations snapped to OpenStreetMap and network model segments in tiploc-location.gpkg

The approach used to overlay and combine data is:

1. create a cropped OSM and centre-line track-model LineString segments within scaled hexagons
2. create line-extended centre-line track-model rectangular polygons within a given hexagon
3. test if the OSM LineStrings are within these rectangular polygons
4. any OSM LineString segments that fall within a centre-line track-model rectangular polygon are discarded.
5. hexagons are classified as to whether they contain no rail, only OSM, only centre-line or a mixture of elements.
6. OSM data in hexagons only containing OSM elements are retained.
7. hexagons with mixed OSM and centre-line data are reassessed but at the next granular hexagon level.
8. the combined OSM only data and centre-line model then seems to give the required result.

The approach used to segment the combined network is:

1. identify waymarks within a rectangle 12 track centre-to-centre separation of the network
2. split linear network features at the near nearest point the the waymark

The centre-to-centre track separation on the rail network is 3.26m

The approach used to identify rail operation STANOX and planning TIPLOC locations is:

1. snap approximate STANOX locations to nearest OSM linear feature (ox layer in tiploc-location.gpkg
2. snap approximate STANOX to combined network-model segement (sx layer in tiploc-location.gpkg
3. use the Network Rail CORPUS open rail reference data to link TIPLOC to STANOX locatation

All code is licensed under Apache 2.0 license, data is licensed under Creative Commons by Share Alike (CC-SA-4.0)