Ordnance Survey – Great Britain's national mapping agency
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Q. Why have roads been selected="selected" as the main search criteria?
A. It is recognised that there are other search criteria that may be of more importance but a line has had to be drawn for the first product release. Subsequent version releases may introduce other search criteria, e.g. the inclusion of geographic names, but this is dependent on customer feedback and a business case.
Q.How are the road extents determined?
A. A ‘box’ has been constructed around each road in each locality and the centre-point of the road link within this ‘box’ is nominated as the reference point for the road. This centre-point determines the town, locality, postcode sector, etc. in which it lies and will be the centre point for displaying the extent of the road on the screen. Coordinates for the minimum and maximum extent of the ‘box’ (x and y coordinates) are included in the product in order to allow the customer to create a screen display of the entire road. Note, the centre of the road link will not always match the centre of the ‘box’.
Q.Why do some of the entries give ‘City of …..’ in the county field?
A. This is because some cities are classified as Unitary Authorities, with the name ‘City of.….’. Smaller towns, villages and other locations will contain the appropriate county name in this data field.
Q. How many road names are there in OS Locator?
A. There are approximately 790 000 road name entities in OS Locator, this is far more than the total number of named and/or classified roads in Great Britain – roads have been divided by locality, e.g. Winchester Road, Bassett and Winchester Road, Shirley both being within the town of Southampton. This also applies where the boundary of a locality runs along a road, the name will appear twice, one entry for each locality on either side of the road.
Q. How are the roads structured?
A. The roads have been divided into localities which means that when a road extends from one area to another it has been divided into each locality. This will enable general searches to be more effective. If a locality boundary runs down the middle of a named road the entry will appear twice in the gazetteer, one for each locality.
Q.Can I search by road number?
A. Yes, if a road is classified according to Highways Authority then each road number has been split by locality and a ‘box’ constructed around its extent.
Q.Are there plans to include other geographic names in OS Locator?
A. This is being assessed as a possibility for a future version release and will be driven by customer demand and a business proposal.
Q. How does OS Locator differ from other OS gazetteers, e.g. 1:50 000 scale gazetteer?
A. The 1:50 000 scale (and 1:250 000 scale) gazetteer is a list of names that appear on the published map of the same scale – this gives little more than a location to where that name can be found on the map. With appropriate software, OS Locator acts like a web browser in being able to search its content using multiple (or a combination of) headings, e.g. search for a road name, in a locality, or by town, or by postcode sector, etc. – then with the appropriate map data backdrop (raster) product you can view the location on your screen.
Q.Why is the postcode only shown to sector level of detail and not the full reference?
A. To include the postcode to full detail level would make it difficult to associate road names. On average there are about 15 houses associated to each postcode, so a single road can contain multiple postcodes. By using postcode sectors this becomes more meaningful in trying to find a location where a general area is known. You could conduct a search for all road names that are centred within a postcode sector should you wish to do so.
Q.How accurate is the information contained within OS Locator?
A. This product is as accurate as the component products from which it is derived. A variety of source data products are used to compile OS Locator so no overall accuracy statement can be applied to this product. The intention is to give a user the ability to find locations using a number of different search criteria so that they can display their area of interest .
Q.What is needed to use OS Locator?
A.Ideally, OS Locator should be used within a geographical information system as a location and/or search tool for reference with 1:10 000 scale raster, 1:25 000 scale raster and OS Street View® as the backdrop mapping.
Q.How often is this product updated?
A. It is updated every six months. This draws on the latest source information that is available from each product when the revision update process starts. Each update will be derived anew from the source data, comprising both new entries and changes to the extent and position of the existing roads. No record of deletions will be available.
Q.Will OS Locator take me exactly to the search location?
A. Location polygons have been created for all of the road features and correspond exactly with their geographic position. However, this might not match the positioning of the name on the map data backdrop product.
Q.I do not require a large area, can I divide this data into smaller sections?
A. It has proved impossible to determine what, if any, divisions could be made in the data that would satisfy the majority of customers. The variety of attribution for each named road should allow the user to create their own sub-dataset, to their own requirements, with ease of using a geographical information system, e.g. by selecting all roads in the City of Southampton and saving the selection to a new file.