Cartographic style definitions
This section defines the default styles for the presentation of data within OS MasterMap. This specifies the colours, fonts, symbols and line styles used for visual display and printing of OS MasterMap. The styles are defined using Scalable Vector Graphics (SVG) syntax.
See W3C SVG Working Group for information on SVG. The Cartographic styling section provides the required information to apply the styles of this section to features.
Style principles
These definitions cover data supplied to customers as part of OS MasterMap by Ordnance Survey.
A style is not provided for all of the information in OS MasterMap due to limitations of generic styling and cartographic information available for specific feature types.
Use of coordinates, stroke-widths and text sizes
All coordinates in this section are specified in eastings and northings in units of metres in the British National Grid.
Stroke widths and text sizes are also specified in units of metres on the ground.
Colour palette
Ordnance Survey has chosen to use colours that are consistent in the internet environment. The colours used are defined with both their RGB and hexadecimal values in the colour palette.
Text
The fonts selected by Ordnance Survey to display text are those that are commonly used with web browsers. A brief description as to how a font is used in SVG is given in the Fonts section.
Symbols
There are two different uses of symbols as defined in the following sections. A base symbol set is defined in Shared symbol geometry section; these may be aggregated to form compound symbols as defined in Compound symbols. Patterns formed from repeating symbols on a predefined grid are specified in Pattern definitions.
Point symbols
Point symbols are used to represent the position of particular features within the data, such as a telephone call box or bollard. The symbol represents the location and type of feature.
Point symbols are applied to the visual representation by translating them to the location of the feature they are representing and rotating them, if the orientation attribute is present, by a given amount.
Fill symbols
Fill symbols are used to represent some attribution of a polygon feature and are distributed as a pattern fill across the polygon. For example, the symbol may represent information about the topographic surface such as the vegetation type.
Because of the overheads of applying pattern fills in many current software systems, pattern fills are optional and depend on user requirements and system capabilities. For example, if a user does not require each mixed vegetation type to be identified graphically, the multiVegetationPattern (as defined in Pattern definitions) could be used to represent all mixed vegetation features.
Line styles
Line styles are used to allow a user to distinguish between different types of linear feature, for example, distinctions may be made to emphasise:
Obstructing detail
Non-obstructing detail
Underground detail
Overhead detail
Building outlines
Water limits and linear features
Landform detail
Narrow-gauge railways
Statutory boundaries
Polygon-closing features
Some lines, particularly those representing the road network, are drawn twice, using first a background style and then an overlay to achieve a multicoloured result. Styles have been defined in this way to produce effects like lines with outlines. This section defines the two components as separate styles. For example, a minor road is first drawn as a black background (carriagewayOutline) that is then overlain with a yellow foreground (minorRoadLine) as below:
The line styles are defined in Line styles.
Fonts
The gml2svg.xsl declares the use of the Arial font for Ordnance Survey’s standard depiction of text string. Within the XSL file, the text colour is dictated by the descriptiveGroup, as is the use of italics. The textRendering complex attribute for a CartographicText feature contains information on the placement, orientation and height for rendering the text.
A font value of 0, 1, 2, or 3 as used in Land-Line® is also provided that can optionally be used for depiction. The suggested fonts for cartographic display are:
– Lutheran (used for non-Roman antiquities)
– Normal – medium Roman font
– Light Roman font (used primarily for building numbers, Roman antiquities, and some administrative names particularly in 1:10 000 areas)
– Suppressed text not supplied in Land-Line due to space limitations.
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