Class: ProjectionMercator

ProjectionMercator()

Represents a Mercator geographic projection.

Constructor

new ProjectionMercator()

Constructs a Mercator geographic projection.
Source:

Extends

Members

(readonly) continuous :boolean

Indicates whether this projection should be treated as continuous with itself. If true, the 2D map will appear to scroll continuously horizontally.
Type:
  • boolean
Inherited From:
Source:

displayName :string

This projection's display name.
Type:
  • string
Inherited From:
Source:

(readonly) is2D :boolean

Indicates whether this projection is a 2D projection.
Type:
  • boolean
Inherited From:
Source:

(readonly) projectionLimits :Sector

Indicates the geographic limits of this projection.
Type:
Inherited From:
Source:

(readonly) stateKey :String

A string identifying this projection's current state. Used to compare states during rendering to determine whether globe-state dependent cached values must be updated. Applications typically do not interact with this property.
Type:
  • String
Source:

Methods

cartesianToGeographic(globe, x, y, z, offset, result) → {Position}

Converts a Cartesian point to a geographic position.
Parameters:
Name Type Description
globe Globe The globe this projection is applied to.
x number The X component of the Cartesian point.
y number The Y component of the Cartesian point.
z number The Z component of the Cartesian point.
offset Vec3 An offset to apply to the Cartesian output points. Typically only projections that are continuous (see continuous) apply this offset. Others ignore it. May be null to indicate that no offset is applied.
result Position A variable in which to return the computed position.
Overrides:
Source:
Throws:
If either the specified globe or result argument is null or undefined.
Type
ArgumentError
Returns:
The specified result argument containing the computed position.
Type
Position

geographicToCartesian(globe, latitude, longitude, elevation, offset, result) → {Vec3}

Converts a geographic position to Cartesian coordinates.
Parameters:
Name Type Description
globe Globe The globe this projection is applied to.
latitude number The latitude of the position, in degrees.
longitude number The longitude of the position, in degrees.
elevation number The elevation of the position, in meters.
offset Vec3 An offset to apply to the Cartesian output. Typically only projections that are continuous (see continuous) apply to this offset. Others ignore it. May be null to indicate no offset is applied.
result Vec3 A variable in which to store the computed Cartesian point.
Overrides:
Source:
Throws:
If the specified globe or result is null or undefined.
Type
ArgumentError
Returns:
The specified result argument containing the computed point.
Type
Vec3

geographicToCartesianGrid(globe, sector, numLat, numLon, elevations, referencePoint, offset, result) → {Float32Array}

Computes a grid of Cartesian points within a specified sector and relative to a specified Cartesian reference point.

This method is used to compute a collection of points within a sector. It is used by tessellators to efficiently generate a tile's interior points. The number of points to generate is indicated by the tileWidth and tileHeight parameters but is one more in each direction. Width refers to the longitudinal direction, height to the latitudinal.

For each implied position within the sector, an elevation value is specified via an array of elevations. The calculation at each position incorporates the associated elevation. There must be (tileWidth + 1) x (tileHeight + 1) elevations in the array.

Parameters:
Name Type Description
globe Globe The globe this projection applies to.
sector Sector The sector in which to compute the points.
numLat Number The number of latitudinal sections a tile is divided into.
numLon Number The number of longitudinal sections a tile is divided into.
elevations Array.<Number> An array of elevations to incorporate in the point calculations. There must be one elevation value in the array for each generated point. Elevations are in meters. There must be (tileWidth + 1) x (tileHeight + 1) elevations in the array.
referencePoint Vec3 The X, Y and Z Cartesian coordinates to subtract from the computed coordinates. This makes the computed coordinates relative to the specified point. May be null.
offset Vec3 An offset to apply to the Cartesian output points. Typically only projections that are continuous (see continuous) apply this offset. Others ignore it. May be null to indicate that no offset is applied.
result Float32Array A typed array to hold the computed coordinates. It must be at least of size (tileWidth + 1) x (tileHeight + 1) * 3. The points are returned in row major order, beginning with the row of minimum latitude.
Overrides:
Source:
Throws:
if any of the specified globe, sector, elevations array or results arrays is null or undefined.
Type
ArgumentError
Returns:
The specified result argument, populated with the computed Cartesian coordinates.
Type
Float32Array

northTangentAtLocation(globe, latitude, longitude, result)

Computes a Cartesian vector that points north and is tangent to the meridian at a specified geographic location.
Parameters:
Name Type Description
globe Globe The globe this projection is applied to.
latitude number The latitude of the location, in degrees.
longitude number The longitude of the location, in degrees.
result Vec3 A variable in which to return the computed vector.
Inherited From:
Source:
Throws:
If either the specified globe or result argument is null or undefined.
Type
ArgumentError

northTangentAtPoint(globe, x, y, z, offset, result)

Computes a Cartesian vector that points north and is tangent to the meridian at a specified Cartesian point.
Parameters:
Name Type Description
globe Globe The globe this projection is applied to.
x number The X component of the Cartesian point.
y number The Y component of the Cartesian point.
z number The Z component of the Cartesian point.
offset Vec3 An offset to apply to the Cartesian point. Typically only projections that are continuous (see continuous) apply this offset. Others ignore it. May be null to indicate that no offset is applied.
result Vec3 A variable in which to return the computed vector.
Inherited From:
Source:
Throws:
If either the specified globe or result argument is null or undefined.
Type
ArgumentError

surfaceNormalAtPoint(globe, x, y, z, result)

Computes the Cartesian surface normal vector at a specified Cartesian point.
Parameters:
Name Type Description
globe Globe The globe this projection is applied to.
x number The X component of the Cartesian point.
y number The Y component of the Cartesian point.
z number The Z component of the Cartesian point.
result Vec3 A variable in which to return the computed vector.
Inherited From:
Source:
Throws:
If either the specified globe or result argument is null or undefined.
Type
ArgumentError