Metadata

The XML metadata for OS Terrain 50 follows the GEMINI metadata standard, which Ordnance Survey has committed to for the UK Location Programme and INSPIRE. Ordnance Survey has provided metadata for national sets of products . OS Terrain 5 and

OS Terrain 50 also have metadata in this form, on a per-tile basis.

The XML metadata contains comments to clarify the meaning of the XML tags used in the file.

Product identification table

Name	Description	Examples
Product name	OS Terrain 50	gmd:MD_DataIdentification/gmd:citation/gmd:CI_Ci tation/gmd:collectiveTitle/gco:CharacterString
Spatial representation	The structure of the data, either grid (DTM) or vector (contours)	gmd:MD_DataIdentification/gmd:spatialRepresentati onType/gmd:MD_SpatialRepresentationTypeC ode
Tile reference	10km National Grid tile reference	gmd:MD_DataIdentification/gmd:citation/gmd:CI_Ci tation/gmd:title/gco:CharacterString
Topic category	INSPIRE theme: elevation	gmd:MD_DataIdentification/gmd:topicCategory/gmd :MD_TopicCategoryCode
Coordinate reference systems	The projected coordinate reference system of British National Grid and the vertical reference system of Ordnance Datum Newlyn	gmd:MD_ReferenceSystem/gmd:referenceSystemIde ntifier/gmd:RS_Identifier/gmd:code/gmx:Anchor xlink:href="urn:ogc:def:crs:EPSG::27700"/British National Grid gmd:MD_ReferenceSystem/gmd:referenceSystemIde ntifier/gmd:RS_Identifier/gmd:code/gmx:Anchor xlink:href="urn:ogc:def:crs:EPSG::5701"/Ordnance Datum Newlyn

Change history table

Name	Description	Examples
Flying date(s)	The date that the area was flown by Ordnance Survey for revision. To accommodate multiple flying dates within the tile, two values will be recorded: the earliest flying date and the latest flying date present. Both dates can be identical. For Profile content, the Date Flown will be recorded as <null>.	gmd:MD_DataIdentification/gmd:extent/gmd:EX_ Extent/gmd:temporalElement/gmd:EX_Temporal Extent/gmd:extent/gml:TimePeriod /gml:beginPosition /gml:endPosition
Processing date	The date the tile was created by Ordnance Survey; not the date of the real-world change or survey.	gmd:MD_DataIdentification/gmd:citation/gmd:CI _Citation/gmd:date/gmd:CI_Date/gmd:date/gco: Date
Version number	An incrementing number to indicate the number of times the tile has been published.	gmd:MD_DataIdentification/gmd:citation/gmd:CI _Citation/gmd:edition/gco:CharacterString
Reason for change	This provides information about the update to the data and whether it is a creation (new) or a revision (modified/verified), which is described in the metadata by using Lineage (see the following row in this table).	gmd:MD_DataIdentification/gmd:citation/gmd:CI _Citation/gmd:date/gmd:CI_Date/gmd:dateType/ gmd:CI_DateTypeCode
Lineage	Text to describe the current status of the tile: ‘created from new imagery’, ‘some parts revised from new imagery’ or ‘new imagery examined and no change’.	gmd:DQ_DataQuality/gmd:lineage/gmd:LI_Lineag e/gmd:statement/gco:CharacterString

Metadata viewing stylesheet

An XSLT viewing style sheet is provided (OSTerrainMetadataViewingStylesheet.xsl) to make the xml easier to read. This style sheet converts the XML to HTML for ease of viewing in a web browser. Some browsers and other software will read this automatically if the user is connected to the internet as its address is referenced in the metadata, but you can also view the style sheet on the Ordnance Survey website.

Example of the metadata XML file

The following box displays a section of the XML file in its native format, with the location of the style sheet highlighted. It can be read like this when opened in an XML viewer or basic file reader.

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="
https://www.ordnancesurvey.co.uk/xml/stylesheet/OSTerrainMetadataViewingStylesheet.xsl
"?>
<gmd:MD_Metadata xmlns:gmd="
http://www.isotc211.org/2005/gmd
" xmlns:gml="
http://www.opengis.net/gml/3.2
" xmlns:xsi="
http://www.w3.org/2001/XMLSchema-instance
" xmlns:gmx="
http://www.isotc211.org/2005/gmx"
 xmlns:gco="
http://www.isotc211.org/2005/gco
" xmlns:xlink="
http://www.w3.org/1999/xlink
" xsi:schemaLocation="
http://www.isotc211.org/2005/gmx
 
http://eden.ign.fr/xsd/isotc211/isofull/20090316/gmx/gmx.xsd
"><!-- Unique identifier, required if this record is being used in a metadata management system -->
<gmd:fileIdentifier>
<gco:CharacterString>OSTerrain5.NT23NE</gco:CharacterString>
</gmd:fileIdentifier>
<gmd:contact gco:nilReason="missing"></gmd:contact>
<gmd:dateStamp>
<gco:DateTime>2013-01-08T03:22:25</gco:DateTime>
</gmd:dateStamp><!-- Projected Coordinate Reference System -->
<gmd:referenceSystemInfo>
<gmd:MD_ReferenceSystem>
<gmd:referenceSystemIdentifier>
<gmd:RS_Identifier>
<gmd:code>
<gmx:Anchor xlink:href="urn:ogc:def:crs:EPSG::27700">British National Grid</gmx:Anchor>

Example of the metadata XML file referencing the XSLT viewing stylesheet

The following box gives an example of how the same XML file displayed in the preceding box will look when it has been converted to HTML by the XSLT viewing style sheet.

OS Terrain Tile Metadata Product identification:

Product name: OS Terrain 5

Spatial representation: grid

Tile reference: NT23NE

Topic category: elevation Coordinate reference systems: British National Grid

Esri grid styling – asc.aux.xml file

The XML file contains min, max, mean and standard deviation height values for the product, in a format defined by Esri. The same values are supplied for every tile. Providing these height statistics is intended to allow colour ramps to be applied by the user, such that adjacent tiles are styled consistently.

This functionality can be disabled by removing the asc.aux.xml file from each downloaded folder or adjusting the parameters of the minimum and maximum heights in a GIS, if desired.