Package gov.nasa.worldwind.globes

Interface GeographicProjection

All Known Implementing Classes:

AbstractGeographicProjection, ProjectionEquirectangular, ProjectionMercator, ProjectionModifiedSinusoidal, ProjectionPolarEquidistant, ProjectionSinusoidal, ProjectionTransverseMercator, ProjectionUPS, ProjectionUTM

public interface GeographicProjection

Defines an interface to project geographic coordinates to Cartesian coordinates. Used by Globe2D implementations to transform geographic coordinates to meters and back.

Each implementation of this interface defines its own constructors, which may accept arguments that completely define the projection.

Method Summary

Modifier and Type	Method	Description
Position	cartesianToGeographic(Globe globe, Vec4 cart, Vec4 offset)	Converts a Cartesian point in meters to a geographic position.
Vec4	geographicToCartesian(Globe globe, Angle latitude, Angle longitude, double metersElevation, Vec4 offset)	Converts a geographic position to meters in Cartesian coordinates.
void	geographicToCartesian(Globe globe, Sector sector, int numLat, int numLon, double[] metersElevation, Vec4 offset, Vec4[] out)	Converts a grid of geographic positions to a grid of points in Cartesian coordinates.
java.lang.String	getName()	Returns the projection name.
Sector	getProjectionLimits()	Indicates the latitude limits for this projection.
boolean	isContinuous()	Indicates whether it makes sense to treat this projection as contiguous with itself.
Vec4	northPointingTangent(Globe globe, Angle latitude, Angle longitude)	Computes a Cartesian vector that points north and is tangent to the meridian at the specified geographic location.
void	setProjectionLimits(Sector projectionLimits)	Specifies the limits for this projection.

Method Detail

getName

java.lang.String getName()

Returns the projection name.

Returns:

The projection name.

isContinuous

boolean isContinuous()

Indicates whether it makes sense to treat this projection as contiguous with itself. If true, the scene controller will make the globe using the projection appear to scroll continuously horizontally.

Returns:

true if it makes sense to treat this projection as continuous, otherwise false.

getProjectionLimits

Sector getProjectionLimits()

Indicates the latitude limits for this projection.

Returns:

The projection limits for this projection.

setProjectionLimits

void setProjectionLimits(Sector projectionLimits)

Specifies the limits for this projection.

Parameters:

projectionLimits - The projection limits.

Throws:

java.lang.IllegalArgumentException - if the specified limits is null or the limits are outside the normal range of latitude or longitude.

geographicToCartesian

Vec4 geographicToCartesian(Globe globe,
                           Angle latitude,
                           Angle longitude,
                           double metersElevation,
                           Vec4 offset)

Converts a geographic position to meters in Cartesian coordinates.

Note: The input arguments are not checked for null prior to being used. The caller, typically a Globe2D implementation, is expected do perform that check prior to calling this method.

Parameters:

globe - The globe this projection is applied to.

latitude - The latitude of the position.

longitude - The longitude of the position.

metersElevation - The elevation of the position, in meters.

offset - An optional offset to be applied to the Cartesian output. Typically only projections that are continuous (see isContinuous() apply this offset. Others ignore it. May be null.

Returns:

The Cartesian point, in meters, corresponding to the input position.

See Also:

cartesianToGeographic(Globe, gov.nasa.worldwind.geom.Vec4, gov.nasa.worldwind.geom.Vec4)

geographicToCartesian

void geographicToCartesian(Globe globe,
                           Sector sector,
                           int numLat,
                           int numLon,
                           double[] metersElevation,
                           Vec4 offset,
                           Vec4[] out)

Converts a grid of geographic positions to a grid of points in Cartesian coordinates.

This method provides an interface for efficient generation of a grid of cartesian points within a sector. The grid is constructed by dividing the sector into numLon x numLat evenly separated points in geographic coordinates. The first and last points in latitude and longitude are placed at the sector's minimum and maximum boundary, and the remaining points are spaced evenly between those boundary points.

For each grid point within the sector, an elevation value is specified via an array of elevations. The calculation at each position incorporates the associated elevation.

Parameters:

globe - The globe this projection is applied to.

sector - The sector over which to generate the points.

numLat - The number of points to generate latitudinally.

numLon - The number of points to generate longitudinally.

metersElevation - An array of elevations to incorporate in the point calculations. There must be one elevation value in the array for each generated point, so the array must have a length of at least numLon x numLat. Elevations are read from this array in row major order, beginning with the row of minimum latitude.

offset - An optional offset to be applied to the Cartesian output. Typically only projections that are continuous (see isContinuous() apply this offset. Others ignore it. May be null.

out - An array to hold the computed cartesian points. It must have a length of at least numLon x numLat. Points are written to this array in row major order, beginning with the row of minimum latitude.

cartesianToGeographic

Position cartesianToGeographic(Globe globe,
                               Vec4 cart,
                               Vec4 offset)

Converts a Cartesian point in meters to a geographic position.

Note: The input arguments are not checked for null prior to being used. The caller, typically a Globe2D implementation, is expected do perform that check prior to calling this method.

Parameters:

globe - The globe this projection is applied to.

cart - The Cartesian point, in meters.

offset - An optional offset to be applied to the Cartesian input prior to converting it. Typically only projections that are continuous (see isContinuous() apply this offset. Others ignore it. May be null.

Returns:

The geographic position corresponding to the input point.

See Also:

geographicToCartesian(Globe, gov.nasa.worldwind.geom.Angle, gov.nasa.worldwind.geom.Angle, double, gov.nasa.worldwind.geom.Vec4)

northPointingTangent

Vec4 northPointingTangent(Globe globe,
                          Angle latitude,
                          Angle longitude)

Computes a Cartesian vector that points north and is tangent to the meridian at the specified geographic location.

Parameters:

globe - The globe this projection is applied to.

latitude - The latitude of the location.

longitude - The longitude of the location.

Returns:

The north pointing tangent corresponding to the input location.