OS NGD Water Network
A Lightning Talk
Last updated
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Ordnance SurveyData
OS Data HubA Lightning Talk
Last updated
There are seven feature types in the OS NGD Water theme: four in the Features collection and three in the Network Collection. The geometry in the Network Collection is the same as OS MasterMap Networks - Water Layer, although the attribution is from OS NGD.
This is a set of links that represent the full water network.
Water Linkset is additional dataset in the Water Network data. This is the same principle as Roads and Streets in the Transport theme.
In OS MasterMap Networks - Water Layer Water Links had a watercourse name but the entire watercourse was not present as a separate feature. In the OS NGD Water Network the full extent of named watercourses now exist as separate features in the Water Linkset data
On the Water Link Feature Type the nameID attribute gives a cross reference between the Water Link and the Water Linkset feature it is part of.
There is also a wtr_ntwk_waterlinkset_wtrlinkref that gives a look-up between the two datasets
The OS NGD Water Network data comes in two formats, CSV and GeoPackage (GPKG)
The GeoPackage format comes ready to load into the GIS package of the users choice with different gpkg files for each layer.
The CSV format is more suited for loading into a database. It has all of the same layers in csv format and all the same attribution as the GeoPackage, however instead of storing the geometry in a GIS ready format, it is stored as a POINT, LINESTRING or MULTILINESTRING attribute with all of the vertices stored as co-ordinate pairs in the text file.
The attribution has changed from the OS MasterMap Networks - Water Layer product:
OS NGD data has an OSID
The features have a TOID, version date and changetype similar to the OS MasterMap family of products, although the TOID is an optional field
There are triple name fields to allow for alternative languages and alternative names. The example shown here is in Wales and has both a CYM and ENG names and an alternative name. Language names also have unique name IDs to distinguish between languages
There is also information about geometry source, description, type, permanence.
Fields exist for catchment name, width and so on, but not all are populated currently
The OSID in the Water Linkset and the Water Linkset ID in the Water Link Reference are the same value
The OSID in Water Link and the Water Link ID in the Water Link Reference are the same value
Ordnance Survey surveyors and remote sensing teams have been capturing and maintaining information on land cover, land use and a more detailed level of description for over 10 years.
The more detailed data has previously been transformed and filtered to match attribution and content for existing products, such as OS MasterMap Networks - Water Layer, however in the OS NGD data it is being published at the original, more granular level.
The new Water Linkset, similar to the Transport Network, has been generated from existing reference data but given a geometry in OS NGD.
Links that may be useful:
This content has been developed from what was originally a Lightning Talk PowerPoint slide set. These slides are available to PSGA members to view and download from the PSGA members area of the OS website
