/// <summary>
/// Serialises a Rectangle into a TomTom skipper record
/// </summary>
/// <param name="Rectangle">The rectangle to serialise</param>
/// <returns>The serialised rectangle</returns>
private byte[] SerialiseRectangle(GeoRect Rectangle) {
byte[] bReturn = new byte[SkipperStructSize];
Int32 AllPOIsSize = SkipperStructSize;
//Calculate Size of POIs
foreach(POI CurrentPOI in Rectangle.POIs) {
AllPOIsSize += GetPOISize(CurrentPOI);
}
//Serialise
bReturn[0] = 0x01;
ConvertToLEBytes(AllPOIsSize).CopyTo(bReturn, 1);
ConvertToLEBytes((Int32)(Rectangle.TopRight.TomTomXPos)).CopyTo(bReturn, 5);
ConvertToLEBytes((Int32)(Rectangle.TopRight.TomTomYPos)).CopyTo(bReturn, 9);
ConvertToLEBytes((Int32)(Rectangle.BottomLeft.TomTomXPos)).CopyTo(bReturn, 13);
ConvertToLEBytes((Int32)(Rectangle.BottomLeft.TomTomYPos)).CopyTo(bReturn, 17);
return bReturn;
}
/// <summary>
/// Creates the OV2 file header
/// </summary>
/// <param name="BoundingRect">The full bounding rectangle for all POIs within the OV2</param>
/// <param name="Rectangles">List containing all rectangles and POIs contained in the OV2</param>
/// <param name="AllPOIs">A list of all POIs within all the calculated rectangles</param>
/// <returns>The byte array file header</returns>
private byte[] GenerateOV2Header(GeoRect BoundingRect, List<GeoRect> Rectangles, List<POI> AllPOIs) {
byte[] bReturn = new byte[SkipperStructSize];
Int32 Size = SkipperStructSize;
//Calculate total size for every POI in the OV2
foreach (POI CurrentPOI in AllPOIs) {
Size += GetPOISize(CurrentPOI);
}
//Calculate total size of all skipper records in teh database
Size += (Rectangles.Count * SkipperStructSize);
//Serialise data
bReturn[0] = 0x01;
ConvertToLEBytes(Size).CopyTo(bReturn, 1);
ConvertToLEBytes((Int32)(BoundingRect.TopRight.TomTomXPos)).CopyTo(bReturn, 5);
ConvertToLEBytes((Int32)(BoundingRect.TopRight.TomTomYPos)).CopyTo(bReturn, 9);
ConvertToLEBytes((Int32)(BoundingRect.BottomLeft.TomTomXPos)).CopyTo(bReturn, 13);
ConvertToLEBytes((Int32)(BoundingRect.BottomLeft.TomTomYPos)).CopyTo(bReturn, 17);
return bReturn;
}
/// <summary>
/// Calculates the full dounding rectangle around a list of POIs
/// </summary>
/// <param name="POIs">The list of POIs</param>
/// <returns>The bounding rectangle</returns>
private GeoRect CalculateBoundingRect(List<POI> POIs) {
GeoRect ReturnRect = new GeoRect();
//Initialise rect with max/min values
ReturnRect.BottomLeft.x = 90; //West co-ordinates are negative, so set to max value
ReturnRect.BottomLeft.y = 180; //South co-ordinates are negative, so set to max value
ReturnRect.TopRight.x = -90; //East co-ordinates are positive, so set to min value
ReturnRect.TopRight.y = -180; //North co-ordinates are positive, so set to min value
//For all POIs
foreach(POI CurrentPOI in POIs) {
//Calculate bounding rectangle for all POIs
if (CurrentPOI.Long < ReturnRect.BottomLeft.x) {
ReturnRect.BottomLeft.x = CurrentPOI.Long;
}
if (CurrentPOI.Long > ReturnRect.TopRight.x) {
ReturnRect.TopRight.x = CurrentPOI.Long;
}
if (CurrentPOI.Lat < ReturnRect.BottomLeft.y) {
ReturnRect.BottomLeft.y = CurrentPOI.Lat;
}
if (CurrentPOI.Lat > ReturnRect.TopRight.y) {
ReturnRect.TopRight.y = CurrentPOI.Lat;
}
}
//All POIs are in this rectangle
ReturnRect.POIs = POIs;
return ReturnRect;
}
/// <summary>
/// Splits a rectangle along its longest side
/// </summary>
/// <param name="Rectangle">The ectangle to split</param>
/// <returns>A list containing the split rectangles</returns>
private List<GeoRect> SplitRectangle(GeoRect Rectangle) {
List<GeoRect> lReturn = new List<GeoRect>();
double NorthSouthDistance = GeoDifference(Rectangle.BottomLeft.y, Rectangle.TopRight.y);
double WestEastDifference = GeoDifference(Rectangle.BottomLeft.x, Rectangle.TopRight.x);
//Is the North to South line the longest?
if (NorthSouthDistance >= WestEastDifference) {
//Split rectangle along North-South
GeoRect TopRect = new GeoRect( new GeoPoint(Rectangle.BottomLeft.x, Rectangle.BottomLeft.y + (NorthSouthDistance / 2)),
new GeoPoint(Rectangle.TopRight.x, Rectangle.TopRight.y)
);
GeoRect BottomRect = new GeoRect( new GeoPoint(Rectangle.BottomLeft.x, Rectangle.BottomLeft.y),
new GeoPoint(Rectangle.TopRight.x, Rectangle.TopRight.y - (NorthSouthDistance / 2))
);
//Add new rectangles to array
lReturn.Add(TopRect);
lReturn.Add(BottomRect);
}
//The West to East line is longest
else {
//Split rectangle along West-East
GeoRect LeftRect = new GeoRect( new GeoPoint(Rectangle.BottomLeft.x, Rectangle.BottomLeft.y),
new GeoPoint(Rectangle.TopRight.x - (WestEastDifference / 2), Rectangle.TopRight.y)
);
GeoRect RightRect = new GeoRect( new GeoPoint(Rectangle.BottomLeft.x + (WestEastDifference / 2), Rectangle.BottomLeft.y),
new GeoPoint(Rectangle.TopRight.x, Rectangle.TopRight.y)
);
//Add new rectangles to array
lReturn.Add(LeftRect);
lReturn.Add(RightRect);
}
return lReturn;
}
/// <summary>
/// Determins if the rectangle is equal to or smaller than the minimum size of a POI bounding rectangle
/// </summary>
/// <param name="Rectangle">The Rectangle</param>
/// <returns>True if the rectangle is equal to or smaller than the minimum size for a POI bounding rectangle</returns>
private bool RectangleIsMinSize(GeoRect Rectangle) {
bool bReturn = false;
if( GeoDifference(Rectangle.BottomLeft.x, Rectangle.TopRight.x) <= minRectSize.Width &&
GeoDifference(Rectangle.BottomLeft.y, Rectangle.TopRight.y) <= minRectSize.Height) {
bReturn = true;
}
return bReturn;
}
/// <summary>
/// Creates a list of rectangles with a maximum of 'MaxPOIsInRectangle' POIs in each rectangle
/// </summary>
/// <param name="Rectangles">The rectangles to process</param>
/// <returns>A list containing the processed rectangles</returns>
private List<GeoRect> ProcessPOIs(GeoRect BoundingRectangle) {
List<GeoRect> lReturn = new List<GeoRect>();
bool bSplitRect = true;
int i = 0;
GeoRect CurrentRect = null;
List<GeoRect> RectsToProcess = new List<GeoRect>();
List<GeoRect> ProcessedRects = null;
//Initialise rectangles to process with full bounding rectangle
RectsToProcess.Add(BoundingRectangle);
//Keep looping until we do not split anything! - Replaced recurrsive call with loop due to stack overflows with large areas!
while(bSplitRect) {
bSplitRect = false;
ProcessedRects = new List<GeoRect>();
for(i = 0; i < RectsToProcess.Count; i++) {
CurrentRect = RectsToProcess[i];
if(CurrentRect.POIs.Count > maxPOIsInRectangle && !RectangleIsMinSize(CurrentRect)) {
//Split the rectangle into 2
List<GeoRect> SplitRectangles = SplitRectangle(CurrentRect);
//Determine which POIs reside in which of the split rectangles
DeterminePOIsInSplitRectangles(SplitRectangles, CurrentRect.POIs);
//Add our 2 new rectangles for further processing
ProcessedRects.AddRange(SplitRectangles);
//We have split the rectangle!
bSplitRect = true;
}
else if (CurrentRect.POIs.Count != 0) {
lReturn.Add(CurrentRect);
}
}
RectsToProcess = new List<GeoRect>(ProcessedRects);
}
return lReturn;
}