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Introduction
The OS MasterMap Highways Network is the definitive Network data supplied by the Ordnance Survey and is the replacement for the ITN Network dataset which was retired in March 2019.
It has been extended to contain much more information about the road and path network in the UK and is updated more frequently.
The tool included with the UK Data Loader will load the data from the source files, in GML format, into a geodatabase and create a routable network dataset.
Which datasets to use
The tools we have written will work with all three sets of data provided by the Ordnance Survey: Roads, Routing and Asset Management and Paths.
If you wish to create a network from the data you should use the Routing and Asset Management data rather than the Roads data as it contains the necessary turn restriction information.
Where you are wishing to use the paths data alongside the other data, copy all of the gz files into the same folder. The UK Data loader will then just load everything from that folder in one go.
Using the tool
Locate the OS MasterMap Highways Toolset and run the tool called “Process OS Highways Data”.
The first parameter you need to enter is the location of your source data. You will need to select the folder which contains the gml or gz files from the Ordnance Survey. The tool will only process files directly inside of that folder, it will not search sub-folders for files to process. This file should contain all the data you wish to load and use in your network, it is not currently possible to combine datasets after they are loaded.
Select the Destination Workspace where the data is to be loaded. You can select either a folder or a database connection
- Where you have selected a folder, you will then be asked to give names to the two file geodatabases that the tool will create.
- Where you have selected an enterprise geodatabase, the feature classes will be created directly under that connection.
You can decide what to do if there are existing datasets with the same name, you can choose to delete all existing data or to append to those datasets.
If you choose to delete the existing data, once the new data is loaded into a featureclass or table any previously existing feature or rows will be removed. If you choose to append the data both existing and new data will remain.
You can also select where to store the log file that will be created.
If you do not wish to create a network dataset and only wish to load the raw data into feature classes and tables then there is the option to select “Data Load Only: Do Not Build A Network”.
Optional Parameters
Name Prefix
There is the option to designate a prefix for the feature class names. This will prefix all of the featureclasses, tables and network datasets created.
Speed Limits
The Ordnance Survey have an option to provide OS MasterMap Highways Network with Speed Limits which identifies the speed limit for a stretch of road based on road traffic signs. This dataset is sourced from local authorities, police forces and many other reliable sources to ensure a high level of accuracy. The data is continuously updated through a system of user feedback
If available, you can enter the location of the Speed Limits shapefile provided to you by the OS
Urban Area
The default speeds applied to a network are based on the road types and classification. This means that an A road will be assigned the same speed whether it is in a rural area or running through a town.
This option can be used to provide an urban area polygon so that different speeds can be applied to roads in urban or rural areas. The OS Zoomstack dataset provide a polygon featureclass which can be used in this tool for free.
Network schema file
If you have previously loaded data and subsequently modified the network dataset with ,for example, alternative speed calculations, you are able to export that configuration to an xml file using a geoprocessing tool.
If you have previously adjusted the network dataset with your own parameters, such as custom speed calculations, you can export that schema as an xml using the Geoprocessing tool in ArcGIS Pro. You can then use this to apply these changes to the network created in this load.
The xml you provide will reference specific dataset names and so you will need to ensure that any dataset prefix you use is consistent between your data loads.
What does the tool do?
How it loads the data
The tool gathers a list of the files to process from the folder and then passes them in batches to the relevant translation tool.
These tools extract the data from the gml/gz files and place them into the relevant feature classes or tables. The data schema it follows can be found on the OS website.
Spatial Indexes are built on the feature classes after the data has finished loading to aid performance.
How it creates the Network
Links and Nodes
The tool extracts the link information from the relevant featureclass and creates a feature classes inside the Network Dataset adding additional information derived from related tables such as whether the link is one way or the grade separation at either end of the link.
Turn Restrictions
In an ArcGIS Network Dataset turn restrictions are set up as geometries that cannot be traversed.
The OS Highways data supplies the Turn Restriction information as a set of tables defining the types of restrictions and the RoadLinks involved in those restrictions.
For a simple restriction the tool takes the RoadLinks involved and creates a turn restriction geometry from those and inserts the restriction feature into the NoTurns featureclass in the Network Dataset.
Mandatory turns
Some turn restrictions in the OS highways dataset define a turn that must be taken. For example, at a cross roads you may be required to pass straight over and not take any other exit.
There is no option within an ArcGIS Network to define a turn that must be taken, we can only specify turns that cannot be taken. Therefore, the tool calculates all the possible turns involved at that intersection, creates turn restriction features for all the manoeuvres that cannot be performed and adds these to the InferredTurns featureclass in the Network Dataset.
The default network configuration
ArcGIS Pro supplies a tool that allows creation of Network Dataset from an XML template. Default network configurations which cover the various combinations of road, ferry and paths data have been supplied in the Resources folder.
Travel modes for driving, cycling and for walking have been included in the templates, and which one is used will depend upon the data present in the data load.
Speeds
The default Network dataset has speeds defined for the all the links based on whether you are walking, cycling or driving.
The driving speeds are set based on the type and designation of the road as defined in the table below.
Driving
| Form of way | RouteHierarchy | Speed (mph) | Urban Speed (mph) |
| All | Motorway | 67 | 67 |
| All | A Road/ A Road Primary | 57 | 25 |
| All | B Road/ B Road Primary | 45 | 25 |
| All | Minor Road | 45 | 24 |
| All | Local Road | 20 | 20 |
| All | other | 10 | 10 |
| Track | All | 5 | 5 |
| Layby | All | 5 | 5 |
Walking speeds have been set to 3mph, cycling has been set to 10mph and the speed on a ferry has been set to 5mph.
Urban/Rural split
Where an urban area featureclass has been specified the tool will calculate how much of each road link is within those urban areas. When calculating the speed along that link it will be proportioned appropriately with the urban or rural speeds quoted above.
OS Speed Limit Data
The Ordnance Survey up until March 2023 supplied a shapefile which contains speed limit information of each Road Link, where that data has been loaded, all other speed calculations will be overridden and that speed used.
Changing speeds
If you wish to modify the calculations used for speeds after the network is created you can do so. This can be done by modifying the scripts used within the “Costs” section of the network setup.
The modified network will then need to be rebuilt.
Full details of the options available in the Network dataset properties dialog can be found in the ArcGIS pro help.
The modified network dataset can then be exported as a template for use in future data loads.
How long will it take to process the data
The table below gives indicative times for how long it will take to process different sizes of data and how long it may take to rebuild the network if it is modified after loading.
The examples below are for loading the full Roads, Routing and Asset Management and Paths data into a file geodatabase.
| Area | Hardware | Data Load | Network Creation and build | Total | Rebuild network |
| Scotland | Virtual Machine
8 Cores 8GB RAM
|
3 hours | 1.5 hours | 4.5 hours | 15 minutes |
| GB | Virtual Machine
8 Cores 30GB RAM
|
20 hours | 9 hours | 29 hours | 30 minutes |
The output
Once the tool has processed the data you will have a set of feature classes and tables containing the raw data. These can be used for visualisation and spatial analysis using the tools available in the ArcGIS Platform.
See the online help for information how to add this data into maps and utilise it in analysis.
The tool will also produce a Network Dataset which can be used in Network analysis in ArcGIS Desktop. It is also suitable for publishing as a Network Analysis service if you have the appropriate installation and licensing of ArcGIS Enterprise.
There is a utility available in ArcGIS Enterprise that will aid you in publishing the Routing services for use in your own portal.
Note: When publishing the Network Dataset created by UK Data Loader to ArcGIS Enterprise 12.0 using the Routing services utility above, some service types require the dataset to include a Time Zone attribute. If this attribute is missing, Enterprise may return error 030353: Network has no time zone attribute. To resolve this, configure a single time zone for the Network Dataset in ArcGIS Pro using the guidance here.