Interface VerticalLineStyle

Defines the reference height used together with VerticalLineStyle.altitudeReference to determine the vertical placement of the line.

Supported values:

• number – Fixed altitude in meters, relative to the global ground plane.
• true – Use the altitude (z) from the feature geometry if present; otherwise 0 m.
• false – Ignore any z-value from the feature geometry and use 0 m.
• 'terrain' – Clamp to the sampled terrain height.

Notes:

• When altitudeReference = 'top', the altitude defines the top of the line; the base is fixed at 0 m.
• When altitudeReference = 'base', the altitude defines the base of the line; the top must be specified using VerticalLineStyle.offsetZ.
• VerticalLineStyle.offsetZ extends the line upward from the reference altitude. With 'terrain', it defines how far above the terrain the line extends.

Examples:

// Top = 100 m, Base = 0 m
{ type: "VerticalLine", altitudeReference: "top", altitude: 100 }

// Base = terrain, Top = terrain + 2 m
{ type: "VerticalLine", altitudeReference: "base", altitude: "terrain", offsetZ: "2m" }

// Base = 0, Top = feature Z (if available)
{ type: "VerticalLine", altitudeReference: "top", altitude: true }

defaultvalue

true

experimental

By default, the meaning of altitude depends on the style type:

• For most flat styles (Circle, Rect, Icon, etc.), altitude defines the center position.
• For VerticalLine, VerticalLineStyle.altitude defines a vertical reference — either the top or the base.

Supported values:

• 'top': the altitude specifies the top of the line; the base is fixed at 0 m (global ground).
• 'base': the altitude specifies the base (bottom) of the line; the top must be defined via VerticalLineStyle.offsetZ.

Notes:

• This property only affects VerticalLine styles; other style types ignore it.
• When VerticalLineStyle.altitude is 'terrain' and altitudeReference is not specified, 'base' is automatically assumed (the line stands on the terrain surface).

defaultvalue

'top'

experimental

Shifts or extends the line relative to its reference altitude.

• Positive values move the line upward.
• Negative values move the line downward.

Units:

• Default is pixels.
• Can also be a string with units (e.g., "1m" for meters).

Special notes for VerticalLine:

• altitudeReference defines which point the altitude value refers to (top or base).
• offsetZ always extends the line upward from the reference point, regardless of whether altitudeReference is 'base' or 'top'.
• With altitude: 'terrain', offsetZ shifts the line relative to the terrain surface.

example

// Move the VerticalLine 8 px upward from its reference
{ type: "VerticalLine", zIndex: 0, stroke: "black", offsetZ: 8 }

// Base = terrain, extend line 1 m upward
{ type: "VerticalLine", zIndex: 0, stroke: "black", altitude: "terrain", altitudeReference: "base", offsetZ: "1m" }

// Top = terrain, extend line 2 m upward
{ type: "VerticalLine", zIndex: 0, stroke: "black", altitude: "terrain", altitudeReference: "top", offsetZ: "2m" }

defaultvalue

1

see

Color for a detailed list of possible supported formats.

example

{...zLayer: 2, zIndex: 5} will be rendered on top of {...zLayer: 1, zIndex: 10}