com.bbn.openmap.proj
Class Cylindrical

java.lang.Object
  com.bbn.openmap.proj.Proj
      com.bbn.openmap.proj.GeoProj
          com.bbn.openmap.proj.Cylindrical

All Implemented Interfaces:

Projection, java.io.Serializable, java.lang.Cloneable

Direct Known Subclasses:

CADRG, LLXY, Mercator

public abstract class Cylindrical
extends GeoProj

Base of all cylindrical projections.

See Also:

Projection, Proj, Mercator, CADRG, Serialized Form

Field Summary

protected int	half_world
protected java.awt.Point	world

Fields inherited from class com.bbn.openmap.proj.GeoProj

DATELINE, mercator, NORTH_POLE, NUM_DEFAULT_CIRCLE_VERTS, NUM_DEFAULT_GREAT_SEGS, pixelsPerMeter, planetPixelCircumference, planetPixelRadius, planetRadius, scaled_radius, SOUTH_POLE, XSCALE_THRESHOLD, XTHRESHOLD

Fields inherited from class com.bbn.openmap.proj.Proj

centerX, centerY, height, maxscale, MIN_HEIGHT, MIN_WIDTH, minscale, projID, rotationAngle, scale, ucuom, width

Constructor Summary

Cylindrical(LatLonPoint center, float scale, int width, int height)
Construct a cylindrical projection.

Method Summary

protected java.util.ArrayList<float[]>	_forwardPoly(double[] rawllpts, int ltype, int nsegs, boolean isFilled) Forward project a raw float[] Poly.
protected java.util.ArrayList<float[]>	_forwardPoly(float[] rawllpts, int ltype, int nsegs, boolean isFilled) Forward project a raw float[] Poly.
protected void	computeParameters() Called when some fundamental parameters change.
static void	dumpPoly(double[] rawllpts, float[] xs, float[] ys)
static void	dumpPoly(float[] rawllpts, float[] xs, float[] ys)
boolean	forwardRaw(double[] rawllpts, int rawoff, float[] xcoords, float[] ycoords, boolean[] visible, int copyoff, int copylen) Forward project a raw array of radian points.
boolean	forwardRaw(float[] rawllpts, int rawoff, float[] xcoords, float[] ycoords, boolean[] visible, int copyoff, int copylen) Forward project a raw array of radian points.
LatLonPoint	getLowerRight() Get the lower right (southeast) point of the projection.
java.lang.String	getName() Get the name string of the projection.
LatLonPoint	getUpperLeft() Get the upper left (northwest) point of the projection.
protected void	init() Called after the center and scale is set in setParams, but before the scale is checked for legitimacy.
java.lang.String	toString() Return string-ified description of this projection.

Methods inherited from class com.bbn.openmap.proj.GeoProj

assertLatLonPoint, clone, doPolyDispatch, doPolyDispatch, forward, forward, forward, forward, forward, forwardArc, forwardArc, forwardArc, forwardCircle, forwardCircle, forwardCircle, forwardGreatPoly, forwardGreatPoly, forwardLine, forwardLine, forwardLLPoly, forwardPoly, forwardPoly, forwardRect, forwardRect, forwardRect, forwardRhumbPoly, forwardRhumbPoly, getCenter, getCenter, getGCTForProjection, getPlanetPixelCircumference, getPlanetPixelRadius, getPlanetRadius, getPPM, getReferenceLon, getScale, getUcuom, inverse, inverse, isComplicatedLineType, isPlotable, normalize_latitude, normalizeLatitude, normalizeLatitude, pan, pan, setCenter, setCenter, setCenter, setPlanetRadius, setPPM, setUcuom, wrap_longitude, wrapLongitude, wrapLongitude, wrapLongitudeDeg

Methods inherited from class com.bbn.openmap.proj.Proj

drawBackground, drawBackground, equals, forward, forward, forward, forwardLine, forwardPoly, forwardPoly, forwardRect, forwardShape, getHeight, getMaxScale, getMinScale, getProjectionID, getRotationAngle, getScale, getWidth, hashCode, inverse, inverse, inverseShape, isPlotable, makeClone, panE, panE, panN, panN, panNE, panNE, panNW, panNW, panS, panS, panSE, panSE, panSW, panSW, panW, panW, setCenter, setHeight, setMaxScale, setMinScale, setParms, setProjectionID, setRotationAngle, setScale, setWidth

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

world

protected transient java.awt.Point world

half_world

protected transient int half_world

Constructor Detail

Cylindrical

public Cylindrical(LatLonPoint center,
                   float scale,
                   int width,
                   int height)

Construct a cylindrical projection.

Parameters:

center - LatLonPoint center of projection

scale - float scale of projection

width - width of screen

height - height of screen

Method Detail

toString

public java.lang.String toString()

Return string-ified description of this projection.

Overrides:

toString in class GeoProj

Returns:

String

See Also:

Projection.getProjectionID()

init

protected void init()

Description copied from class: Proj

Called after the center and scale is set in setParams, but before the scale is checked for legitimacy. This is an opportunity to set constants in subclasses before anything else gets called or checked for validity. This is different than computeParameters() which is called after some checks. This is a good time to pre-calculate constants and set maxscale and minscale.

Make sure you call super.init() if you override this method.

Overrides:

init in class GeoProj

computeParameters

protected void computeParameters()

Called when some fundamental parameters change.

Each projection will decide how to respond to this change. For instance, they may need to recalculate "constant" parameters used in the forward() and inverse() calls.

Specified by:

computeParameters in class Proj

getUpperLeft

public LatLonPoint getUpperLeft()

Get the upper left (northwest) point of the projection.

Returns the upper left point (or closest equivalent) of the projection based on the center point and height and width of screen.

Specified by:

getUpperLeft in interface Projection

Overrides:

getUpperLeft in class Proj

Returns:

LatLonPoint

getLowerRight

public LatLonPoint getLowerRight()

Get the lower right (southeast) point of the projection.

Returns the lower right point (or closest equivalent) of the projection based on the center point and height and width of screen.

Specified by:

getLowerRight in interface Projection

Overrides:

getLowerRight in class Proj

Returns:

LatLonPoint

forwardRaw

public boolean forwardRaw(float[] rawllpts,
                          int rawoff,
                          float[] xcoords,
                          float[] ycoords,
                          boolean[] visible,
                          int copyoff,
                          int copylen)

Forward project a raw array of radian points. This assumes nothing about the array of coordinates. In no way does it assume the points are connected or that the composite figure is to be filled.

It does populate a visible array indicating whether the points are visible on the projected view of the world.

Specified by:

forwardRaw in interface Projection

Overrides:

forwardRaw in class Proj

Parameters:

rawllpts - array of lat,lon,... in radians

rawoff - offset into rawllpts

xcoords - x coordinates

ycoords - y coordinates

visible - coordinates visible?

copyoff - offset into x,y,visible arrays

copylen - number of coordinates (coordinate arrays should be at least this long, rawllpts should be at least twice as long).

Returns:

boolean true if all points visible, false if some points not visible.

forwardRaw

public boolean forwardRaw(double[] rawllpts,
                          int rawoff,
                          float[] xcoords,
                          float[] ycoords,
                          boolean[] visible,
                          int copyoff,
                          int copylen)

Forward project a raw array of radian points. This assumes nothing about the array of coordinates. In no way does it assume the points are connected or that the composite figure is to be filled.

It does populate a visible array indicating whether the points are visible on the projected view of the world.

Specified by:

forwardRaw in interface Projection

Overrides:

forwardRaw in class Proj

Parameters:

rawllpts - array of lat,lon,... in radians

rawoff - offset into rawllpts

xcoords - x coordinates

ycoords - y coordinates

visible - coordinates visible?

copyoff - offset into x,y,visible arrays

copylen - number of coordinates (coordinate arrays should be at least this long, rawllpts should be at least twice as long).

Returns:

boolean true if all points visible, false if some points not visible.

_forwardPoly

protected java.util.ArrayList<float[]> _forwardPoly(float[] rawllpts,
                                                    int ltype,
                                                    int nsegs,
                                                    boolean isFilled)

Forward project a raw float[] Poly.

Implementation:
For the cylindrical "boxy" family of projections, we project all the points, and check the horizontal (longitudinal) spacing between vertices as we go. If the spacing is greater than half the world width (circumference) in pixels, we assume that the segment has wrapped off one edge of the screen and back onto the other side. (NOTE that our restrictions on line segments mentioned in the Projection interface do not allow for lines >= 180 degrees of arc or for the difference in longitude between two points to be >= 180 degrees of arc).

For the case where a segment wraps offscreen, we keep track of the wrapping adjustment factor, and shift the points as we go. After projecting and shifting all the points, we have a single continuous x-y polygon. We then need to make shifted copies of this polygon for the maxima and minima wrap values calculated during the projection process. This allows us to see the discontinuous (wrapped) sections on the screen when they are drawn.

Specified by:

_forwardPoly in class GeoProj

Parameters:

rawllpts - float[] of lat,lon,lat,lon,... in RADIANS!

ltype - line type (straight, rhumbline, greatcircle)

nsegs - number of segments between vertices (or if < 0, generate this value internally)

isFilled - filled poly? this is currently ignored for cylindrical projections.

Returns:

ArrayList of x[], y[], x[], y[], ... the projected poly

_forwardPoly

protected java.util.ArrayList<float[]> _forwardPoly(double[] rawllpts,
                                                    int ltype,
                                                    int nsegs,
                                                    boolean isFilled)

Forward project a raw float[] Poly.

Implementation:
For the cylindrical "boxy" family of projections, we project all the points, and check the horizontal (longitudinal) spacing between vertices as we go. If the spacing is greater than half the world width (circumference) in pixels, we assume that the segment has wrapped off one edge of the screen and back onto the other side. (NOTE that our restrictions on line segments mentioned in the Projection interface do not allow for lines >= 180 degrees of arc or for the difference in longitude between two points to be >= 180 degrees of arc).

For the case where a segment wraps offscreen, we keep track of the wrapping adjustment factor, and shift the points as we go. After projecting and shifting all the points, we have a single continuous x-y polygon. We then need to make shifted copies of this polygon for the maxima and minima wrap values calculated during the projection process. This allows us to see the discontinuous (wrapped) sections on the screen when they are drawn.

Specified by:

_forwardPoly in class GeoProj

Parameters:

rawllpts - float[] of lat,lon,lat,lon,... in RADIANS!

ltype - line type (straight, rhumbline, greatcircle)

nsegs - number of segments between vertices (or if < 0, generate this value internally)

isFilled - filled poly? this is currently ignored for cylindrical projections.

Returns:

ArrayList of x[], y[], x[], y[], ... the projected poly

dumpPoly

public static final void dumpPoly(float[] rawllpts,
                                  float[] xs,
                                  float[] ys)

dumpPoly

public static final void dumpPoly(double[] rawllpts,
                                  float[] xs,
                                  float[] ys)

getName

public java.lang.String getName()

Get the name string of the projection.

Specified by:

getName in interface Projection

Overrides:

getName in class Proj