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Introduction
OS MasterMap Topography Layer® is the most detailed and accurate view of Great Britain’s landscape – from roads to fields, to buildings and trees, fences, paths and more.
The tool included in the UK Data Loader will load the data from the source files, in zipped GML format, into a geodatabase. The tool will also allow you to apply a Change Only Update (COU) to an existing dataset
Considerations when applying Change Only Updates
The UK data Loader has the ability to process Change Only updates for the OS MasterMap Topography layer.
However, due to changes in the underlying data schema the COU can only be applied to data created by the UK Data Loader.
Therefore, if you have data previously loaded using ProductivitySuite you will need to perform a new initial load of the data the first time you move to the UK Data Loader. Following that COU can be applied
Using the tool
Initial Load
Locate the OS MasterMap Topography Layer Toolset and run the script called “Load OSMM Topography Data”.
Enter the location of your source data. Select the folder which contains the gz files from the Ordnance Survey. The tool will also search sub-folders for files to process. The tool will process the first order number it detects in that location. The data in a single order is not required to be contiguous. If you have multiple orders that you wish to combine, then you should process them separately and use the out of the box tools to append one dataset with the other.
Select the Existing Destination Workspace where the data is to be loaded. You can select either a file geodatabase or an enterprise geodatabase connection.
Select where to store the log file that will be created.
There is the option to designate a prefix for the feature class names.
The is also an option create Annotation Line Features. Selecting this option will generate a line feature class which corresponds to length and orientation of the annotation text. This option requires an ArcGIS Desktop Standard licence to function.
Applying a COU to an existing dataset
Locate the OS MasterMap Topography Layer Toolset and run the script called “Apply COU To Existing OSMM Topography Data”.
Enter the location of the source data. Select the folder which contains the gz files from the Ordnance Survey. The tool will also search sub-folders for files to process.
Select the Existing Destination Workspace where the data is to be loaded. You can select either a file geodatabase or a database connection.
Select where to store the log file that will be created.
The tool will interrogate the destination and provide a drop down of any existing Topography datasets, select the one that the COU is to be applied to.
What does the tool do?
How it loads the data
The tool gathers a list of the files to process from the folder. It will then create a table in the destination which lists the files and their current processed status.
Each file is then sent to the Spatial ETL tool which will extract the feature into the relevant feature classes in your destination.
In addition the tool will add two fields to the feature classes for style codes and descriptions to allow the loaded data to be used with the Ordnance Surveys styling published through GitHub with no further processing required. For details see the section on styling the data below.
For the annotation line feature class, the features are created by taking the bounding box of the text in the annotation featureclass and extracting the centre line. The centre line is digitised in the direct of the text (left to right as it is read) .
Once complete the file will be marked as processed and the next passed to the tool.
After all files are processed the tool will add an index to each feature class based on the TOID field and remove any duplicates.
Handling errors
If one of the files fails it will be marked as such, the load rolled back to the end of the previous file and the next file passed into the tool. At the end of the load all failed files will be retried. If the file subsequently fails to load again the log file should be checked for further details on why the load failed and reported to technical support for assistance.
If for any reason the process is interrupted during a load, if the tool is run again with the same parameters it will pick up from the last completed file and proceed to load all of the remaining files until complete.
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. Choosing to create the annotation line feature class can increase these processing time.
| Area | Total number of features | Hardware | Initial Data Load | COU (will vary depending on volume of changes) |
| All ST files | 26,767,583 | Virtual Machine
4 Cores 8GB RAM
|
13 hours | 3 hours |
| All TQ files | 67,856,858 | Virtual Machine
4 Cores 8GB RAM
|
40 hours | 6 hours |
| GB | 497,306,702 | Virtual machine
4 Cores 8GB RAM
|
9.5 days | 2.5 days |
Styling the data
The tool adds the styling codes required by the Ordnance Surveys style sheets published through GitHub.
The Ordnance survey publish a getting started guide along with the layer files which explains how to repoint the layers at the new data sources. For reference below is a list of how the featureclasses created by the UK Data Loader map to the layers in the layers in the style.
| OS stylesheet layer | FeatureClass |
| CartographicText | AnnoPoint |
| CartographicSymbol | Sym |
| BoundaryLine | Bnd |
| TopographicPoint | Pnt |
| TopographicLine | Line |
| TopographicArea | Area |
Note: Ensure that if using the OS stylesheets to set the reference scale to 1:2000 as per the user guide they provide.
Labelling
The UK Data loader produces an annotation feature class called AnFC when it processes the data. Where possible we recommend using that for your labels.
Alternatively, you can use the AnnoPoint featureclass with the OS styles as above.
It is also possible to use the AnnoLine featureclass (if it has been generated) but you will need to setup your own label classes in order to style them as you want them to appear.