RasterMapEntry

java.lang.Object
- org.ka2ddo.yaac.gui.rastermap.RasterMapEntry

All Implemented Interfaces:

java.io.Serializable
```
public class RasterMapEntry
extends java.lang.Object
implements java.io.Serializable
```
This class describes one raster map image file and the translation information needed to render it on the screen with the correct registration.
Because of the distortion caused by projecting a nearly-spherical Earth onto a flat map panel view, the image re-registration algorithm assumes a trapezoidal distortion as a good-enough approximation for rasters in units of meters (or other linear length), so the Java AffineTransform is insufficient to project raster map images into the map viewport. Instead, the following equations are used to map viewport pixel coordinates into raster map image pixel coordinates: x_i = x0 + x1 * x_v + x2 * y_v + x3 * x_v * y_v y_i = y0 + y1 * y_v + y2 * x_v + y3 * y_v * x_v
To compute the coefficients of the above equations, the least squares method is used to fit a series of pinpoints (associations between image pixels and geographical map coordinates) into the mapping between viewport pixel coordinates and image pixel coordinates.
If the raster image pixel step is in units of fractional degrees (for example, US National Weather Service radar maps), the full Mercator projection is needed to convert between degree-based image coordinates and linear pixel-based viewport coordinates.
x_i = x0 + x1 * x_v y_i = y0 + y1 * atan(sinh(y3 * y_v + y2)) and, unlike the linear formula, the Mercator formula does not allow for any relative rotation of coordinate systems.

Author:

Andrew Pavlin, KA2DDO

See Also:

Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`RasterMapEntry.PinPoint` This class contains one association between a pixel in the image and its latitude/longitude position on the planet.

Field Summary

Fields
Modifier and Type	Field and Description
`boolean`	`enabled` Flag indicating whether this particular raster overlay should be displayed in the map.
`int`	`height` Height of raster image in pixels.
`java.awt.image.BufferedImage`	`img` The image as a renderable object (assuming it can be loaded successfully).
`java.util.Date`	`imgCreationDate` Timestamp when the image was created (used to detect an updated image for automatic refreshing).
`boolean`	`isLinear` Indicates that the steps between pixels are in units of linear distance (meters), rather than in angular distance (degrees) across the approximately spherical Earth.
`boolean`	`keepImg` Indicates whether local storage is available for image so it can be quickly reloaded.
`java.lang.String`	`pathname` Pathname to where the image file is stored on this computer.
`boolean`	`persist` Flag indicating whether this particular raster overlay should be persisted over YAAC restarts.
`java.util.ArrayList<RasterMapEntry.PinPoint>`	`pinpointList` The list of PinPoints matching image pixels with global lat/lon positions.
`int`	`transparency` The level of transparency fading to apply to the raster map (alpha component).
`java.awt.Color`	`transparentColor` The color of the raster image that is to be replaced with full transparency, so the map behind the raster image can still be seen.
`int`	`width` Width of raster image in pixels.

Constructor Summary

Constructors
Constructor and Description

RasterMapEntry()

Constructors
Constructor and Description
`RasterMapEntry()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`RasterMapEntry.PinPoint`	`getPinPointAt(int vx, int vy, com.bbn.openmap.proj.Projection proj)` Find which (if any) PinPoint that the specified viewport coordinates are upon.
`java.awt.geom.Rectangle2D.Float`	`getViewportBounds2DOfImage(int vWidth, int vHeight, com.bbn.openmap.proj.Mercator projection)` Get the coordinates within the viewport that intersect the raster image.
`void`	`read(java.io.DataInput dis)` Read a serialized dump of this object from an input stream for restoration.
`void`	`removePersistence(java.util.prefs.Preferences prefs)` Remove this RasterMapEntry from the Preferences persistence cache.
`java.lang.String`	`toString()` Returns a string representation of the object.
`java.awt.geom.Point2D.Float`	`transformImageToViewport(float xi, float yi, java.awt.geom.Point2D.Float dstPt, com.bbn.openmap.proj.Mercator projection)` Convert coordinates within an image into viewport coordinates.
`java.awt.geom.Point2D.Float`	`transformViewportToImage(float vx, float vy, java.awt.geom.Point2D.Float dstPt, com.bbn.openmap.proj.Mercator projection)` Convert viewport coordinates into a position within the raster image.
`void`	`write(java.io.DataOutput dos)` Write a serialized dump of this object to an output stream for storage and later restoration.
`void`	`writeToPreferences(java.util.prefs.Preferences prefs)` Write a serialized dump of this object to Java Preferences.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - pathname
```
public java.lang.String pathname
```
    Pathname to where the image file is stored on this computer.
  - img
```
public transient java.awt.image.BufferedImage img
```
    The image as a renderable object (assuming it can be loaded successfully).
  - width
```
public int width
```
    Width of raster image in pixels.
  - height
```
public int height
```
    Height of raster image in pixels.
  - transparentColor
```
public java.awt.Color transparentColor
```
    The color of the raster image that is to be replaced with full transparency, so the map behind the raster image can still be seen.
  - transparency
```
public int transparency
```
    The level of transparency fading to apply to the raster map (alpha component).
  - enabled
```
public boolean enabled
```
    Flag indicating whether this particular raster overlay should be displayed in the map.
  - persist
```
public boolean persist
```
    Flag indicating whether this particular raster overlay should be persisted over YAAC restarts.
  - imgCreationDate
```
public transient java.util.Date imgCreationDate
```
    Timestamp when the image was created (used to detect an updated image for automatic refreshing).
  - isLinear
```
public boolean isLinear
```
    Indicates that the steps between pixels are in units of linear distance (meters), rather than in angular distance (degrees) across the approximately spherical Earth. This affects the formula used for Mercator projection of the image into the viewport.
  - keepImg
```
public boolean keepImg
```
    Indicates whether local storage is available for image so it can be quickly reloaded. Should be true for network-provided images that would be expensive to reload.
  - pinpointList
```
public final java.util.ArrayList<RasterMapEntry.PinPoint> pinpointList
```
    The list of PinPoints matching image pixels with global lat/lon positions.
- Constructor Detail
  - RasterMapEntry
```
public RasterMapEntry()
```
- Method Detail
  - transformViewportToImage
```
public final java.awt.geom.Point2D.Float transformViewportToImage(float vx,
                                                                  float vy,
                                                                  java.awt.geom.Point2D.Float dstPt,
                                                                  com.bbn.openmap.proj.Mercator projection)
```
    Convert viewport coordinates into a position within the raster image.
    
    Parameters:
    
    vx - X coordinate of point in the viewport
    
    vy - Y coordinate of point in the viewport
    
    dstPt - Point2D.Float object to contain the answer, or null to allocate a new Point2D.Float object
    
    projection - Mercator projection used to translate coordinates (only needed for degree-scaled rasters)
    
    Returns:
    
    raster image pixel coordinates corresponding to the viewport coordinates
  - transformImageToViewport
```
public java.awt.geom.Point2D.Float transformImageToViewport(float xi,
                                                            float yi,
                                                            java.awt.geom.Point2D.Float dstPt,
                                                            com.bbn.openmap.proj.Mercator projection)
```
    Convert coordinates within an image into viewport coordinates.
    
    Parameters:
    
    xi - X coordinate of pixel within the raster image
    
    yi - Y coordinate of pixel within the raster image
    
    dstPt - Point2D.Float object to contain the answer, or null to allocate a new Point2D.Float object
    
    projection - Mercator projection used to translate coordinates (only needed for degree-scaled rasters)
    
    Returns:
    
    viewport coordinates for the specified position within the image
  - getViewportBounds2DOfImage
```
public java.awt.geom.Rectangle2D.Float getViewportBounds2DOfImage(int vWidth,
                                                                  int vHeight,
                                                                  com.bbn.openmap.proj.Mercator projection)
```
    Get the coordinates within the viewport that intersect the raster image.
    
    Parameters:
    
    vWidth - viewport width in pixels
    
    vHeight - viewport height in pixels
    
    projection - Mercator projection used to translate coordinates (only needed for degree-scaled rasters)
    
    Returns:
    
    Rectangle2D of viewport coordinates bounding the image, or null if no intersection
  - getPinPointAt
```
public RasterMapEntry.PinPoint getPinPointAt(int vx,
                                             int vy,
                                             com.bbn.openmap.proj.Projection proj)
```
    Find which (if any) PinPoint that the specified viewport coordinates are upon.
    
    Parameters:
    
    vx - viewport X coordinate
    
    vy - viewport Y coordinate
    
    proj - Projection of the current viewport
    
    Returns:
    
    PinPoint at the specified viewport coordinates, or null if no matching PinPoint found
  - read
```
public void read(java.io.DataInput dis)
          throws java.io.IOException
```
    Read a serialized dump of this object from an input stream for restoration.
    
    Parameters:
    
    dis - DataInput object to read the object data from
    
    Throws:
    
    java.io.IOException - if read fails for any reason
  - write
```
public void write(java.io.DataOutput dos)
           throws java.io.IOException
```
    Write a serialized dump of this object to an output stream for storage and later restoration. Note this does not write the persist flag, as this code wouldn't be getting called if the record wasn't supposed to be persisted.
    
    Parameters:
    
    dos - DataOutput object to write the RasterMapEntry to
    
    Throws:
    
    java.io.IOException - if write fails for any reason
  - writeToPreferences
```
public void writeToPreferences(java.util.prefs.Preferences prefs)
```
    Write a serialized dump of this object to Java Preferences.
    
    Parameters:
    
    prefs - Preferences object to store this object
  - removePersistence
```
public void removePersistence(java.util.prefs.Preferences prefs)
```
    Remove this RasterMapEntry from the Preferences persistence cache.
    
    Parameters:
    
    prefs - Preferences object supposedly containing an entry for this RasterMapEntry
  - toString
```
public java.lang.String toString()
```
    Returns a string representation of the object.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    a string representation of the RasterMapEntry.

Class RasterMapEntry

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

pathname

img

width

height

transparentColor

transparency

enabled

persist

imgCreationDate

isLinear

keepImg

pinpointList

Constructor Detail

RasterMapEntry

Method Detail

transformViewportToImage

transformImageToViewport

getViewportBounds2DOfImage

getPinPointAt

read

write

writeToPreferences

removePersistence

toString