This section describes the single feature type that makes up the OS MasterMap Topography Layer – Building Height Attribute product. The Building Height Attribute feature type has 10 attributes. The following information is given about each attribute:
The name of the attribute and what it is describing.
The nature of the attribute. The following values may occur:
| Type | Description |
|---|---|
Describes how many times this element is expected to be populated in the data. An attribute may be optional or mandatory within the product as denoted by the following:
[1] indicates that the attribute is mandatory and can only occur once.
[0..1] indicates that the attribute is optional; if present, it only occurs once.
Date
Specifies a day within the Gregorian calendar in the format YYYY-MM-DD.
Integer
Any positive or negative whole number or zero.
Real
A floating point number.
CharacterString
An ordered set of characters.
Unique feature identifier of the topographicArea building polygon taken from OS MasterMap Topography Layer.
Type: CharacterString
Length: 20
Multiplicity: [1]
The version number of the TOID for which the height values have been calculated.
Type: Integer
Length: 3
Multiplicity: [1]
The date that the Building Height Attribute values were calculated for the given OS_TOPO_TOID. Dates will follow the structure YYYY-MM-DD.
Type: Date
Length: 10
Multiplicity: [1]
The 5km² tile reference within which the Building Height Attribute is located.
Type: CharacterString
Length: 6
Multiplicity: [1]
AbsHMin is the absolute minimum height of the intersection of the external building walls and the underlying ground surface.
Type: Real
Length: 4.1
Multiplicity: [1]
AbsH2 is the absolute height of the base of the roof, that is, where the roof intersects the principal part of the building. The principal part of the building is defined as the main structure.
Type: Real
Length: 4.1
Multiplicity: [0..1]
AbsHMax is the absolute height of the highest point on the building and can include any structure, such as chimneys, plant housings and machinery.
Type: Real
Length: 4.1
Multiplicity: [0..1]
RelH2 = AbsH2 – AbsHMin. RelH2 is the relative building height from the base of the building (AbsHMin) to the height of the base of the roof (AbsH2).
Type: Real
Length: 4.1
Multiplicity: [0..1]
RelHMax = AbsHMax – AbsHMin. RelHMax is the relative building height from the base of the building (AbsHMin) to the height of the highest point on the building (AbsHMax).
Type: Real
Length: 4.1
Multiplicity: [0..1]
A qualitative assessment of the confidence of the height statistics for each topographicArea building polygon.
Type: BHA_ConfValue
Length: 2
Multiplicity: [1]