de.topobyte.mercator.image

Class MercatorImage

java.lang.Object

de.topobyte.mercator.image.MercatorImage

All Implemented Interfaces:

CoordinateTransformer

public class MercatorImage
extends Object
implements CoordinateTransformer

An image that shows a part of the world using Mercator projection. It is constructed from a defining bounding box and some pixel width and height. The MercatorImage is constructed such that the whole defining bounding box is visible within the image. That means that the image may actually represent a bigger bounding box than the one that was used at construction time. This is called the visible bounding box. The bounding box used for object creation is called the defining bounding box. The MercatorImage implements the CoordinateTransformer interface and thereby transforms lon/lat coordinates to pixel coordinates on the image.

Constructor Summary

Constructors

Constructor and Description
MercatorImage(BBox bbox, int width, int height) Create a new MercatorImage with the given size and positional information.
MercatorImage(double lon1, double lat1, double lon2, double lat2, int width, int height) Create a new MercatorImage with the given size and positional information.

Method Summary

Modifier and Type	Method and Description
BBox	getDefiningBoundingBox() Get the bounding box that was used to create this image.
int	getHeight()
double	getImageSx() The image shows a part of the whole world, which is projected onto a Mercator square whose size can be obtained using getWorldSize().
double	getImageSy() The image shows a part of the whole world, which is projected onto a Mercator square whose size can be obtained using getWorldSize().
double	getLat1()
double	getLat2()
double	getLon1()
double	getLon2()
BBox	getVisibleBoundingBox() Get the bounding box that is really visible on the image.
int	getWidth()
double	getWorldSize() The image shows a part of the whole world which is projected onto a Mercator square, whose size can be obtained using this method.
double	getX(double lon)
double	getY(double lat)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MercatorImage

public MercatorImage(BBox bbox,
                     int width,
                     int height)

Create a new MercatorImage with the given size and positional information.

Parameters:

bbox - the bbox to cover.

width - the width of the image.

height - the height of the image.

MercatorImage

public MercatorImage(double lon1,
                     double lat1,
                     double lon2,
                     double lat2,
                     int width,
                     int height)

Create a new MercatorImage with the given size and positional information.

Parameters:

lon1 - leftmost longitude.

lat1 - top latitude.

lon2 - rightmost longitude.

lat2 - bottom latitude.

width - the width of the image in pixels.

height - the height of the image in pixels.

Method Detail

getX

public double getX(double lon)

Specified by:

getX in interface CoordinateTransformer

getY

public double getY(double lat)

Specified by:

getY in interface CoordinateTransformer

getDefiningBoundingBox

public BBox getDefiningBoundingBox()

Get the bounding box that was used to create this image. Note that this may be different from the visible bounding box.

Returns:

the defining bounding box

getVisibleBoundingBox

public BBox getVisibleBoundingBox()

Get the bounding box that is really visible on the image. This box may differ from the input bounding box, because the image contains the whole input bounding box and may thus show an actual bounding box that is bigger.

Returns:

the visible bounding box

getWidth

public int getWidth()

Returns:

the width of the image in pixels.

getHeight

public int getHeight()

Returns:

the height of the image in pixels.

getLon1

public double getLon1()

Returns:

the leftmost longitude of the defining bounding box.

getLat1

public double getLat1()

Returns:

the top latitude of the defining bounding box.

getLon2

public double getLon2()

Returns:

the rightmost longitude of the defining bounding box.

getLat2

public double getLat2()

Returns:

the bottom latitude of the defining bounding box.

getImageSx

public double getImageSx()

The image shows a part of the whole world, which is projected onto a Mercator square whose size can be obtained using getWorldSize(). Get the relative position of the visible part of the image on this Mercator square in image space units.

Returns:

the x coordinate in image space where the specified leftmost coordinate is.

getImageSy

public double getImageSy()

The image shows a part of the whole world, which is projected onto a Mercator square whose size can be obtained using getWorldSize(). Get the relative position of the visible part of the image on this Mercator square in image space units.

Returns:

the y coordinate in image space where the specified top coordinate is.

getWorldSize

public double getWorldSize()

The image shows a part of the whole world which is projected onto a Mercator square, whose size can be obtained using this method.

Returns:

the internal scale used. This is equivalent to the Mercator worldsize, i.e. the size in pixels of an image that would show the whole world.