public int CompareTo(object obj)
{
MissingElevation me2 = (MissingElevation)obj;
int c = missingNeighbours.CompareTo(me2.missingNeighbours);
if (c != 0)
{
return(c);
}
c = lng.CompareTo(me2.lng);
if (c != 0)
{
return(c);
}
return(lat.CompareTo(me2.lat));
}
static private double CalculateNeighbours(IRasterDigitalElevationModel dem, MissingElevation me)
{
double interpolatedElevation = 0;
me.MissingNeighbours = 0;
if (me.Lng > 0)
{
double elevation = dem.GetElevationForDataPoint(me.Lng - 1, me.Lat);
if (elevation == Int16.MinValue)
{
me.MissingNeighbours++;
}
else
{
interpolatedElevation += elevation;
}
}
else
{
me.MissingNeighbours++;
}
if (me.Lng < dem.LonLength - 1)
{
double elevation = dem.GetElevationForDataPoint(me.Lng + 1, me.Lat);
if (elevation == Int16.MinValue)
{
me.MissingNeighbours++;
}
else
{
interpolatedElevation += elevation;
}
}
else
{
me.MissingNeighbours++;
}
if (me.Lat > 0)
{
double elevation = dem.GetElevationForDataPoint(me.Lng, me.Lat - 1);
if (elevation == Int16.MinValue)
{
me.MissingNeighbours++;
}
else
{
interpolatedElevation += elevation;
}
}
else
{
me.MissingNeighbours++;
}
if (me.Lat < dem.LatLength - 1)
{
double elevation = dem.GetElevationForDataPoint(me.Lng, me.Lat + 1);
if (elevation == Int16.MinValue)
{
me.MissingNeighbours++;
}
else
{
interpolatedElevation += elevation;
}
}
else
{
me.MissingNeighbours++;
}
if (me.MissingNeighbours < 4)
{
interpolatedElevation /= (4 - me.MissingNeighbours);
}
else
{
interpolatedElevation = 0;
}
return(interpolatedElevation);
}
public IRasterDigitalElevationModel Process(IRasterDigitalElevationModel input)
{
// clone data
IRasterDigitalElevationModel output = input.Clone() as IRasterDigitalElevationModel;
SortedList <MissingElevation, Point2 <double> > missingElevations = new SortedList <MissingElevation, Point2 <double> > ();
// find all missing elevations
for (int x = 0; x < output.LonLength; x++)
{
for (int y = 0; y < output.LatLength; y++)
{
double elevation = output.GetElevationForDataPoint(x, y);
if (elevation == double.MinValue)
{
MissingElevation me = new MissingElevation();
me.Lng = x;
me.Lat = y;
// now calculate missing neighbours count
CalculateNeighbours(output, me);
// now add it to the list
missingElevations.Add(me, new Point2 <double> (me.Lng, me.Lat));
}
}
}
int startingMissingElevations = missingElevations.Count;
// while there are missing elevations
while (missingElevations.Count > 0)
{
// use first missing elevation
MissingElevation me = missingElevations.Keys[0];
// based on the neighbouring non-missing data, calculate interpolated elevation
double interpolatedElevation = CalculateNeighbours(output, me);
// enter this elevation into the output ElevationData
output.SetElevationForDataPoint(me.Lng, me.Lat, interpolatedElevation);
// remove this elevation from missing elevation list
missingElevations.Remove(me);
// for each neighbour which is also missing elevation:
// decrease the missingNeighbours counter
// and reposition the neighbour in the missing elevations list
Point2 <double>[] neighbourPoints = { new Point2 <double> (me.Lng - 1, me.Lat),
new Point2 <double> (me.Lng + 1, me.Lat),new Point2 <double> (me.Lng, me.Lat - 1),
new Point2 <double> (me.Lng, me.Lat + 1) };
for (int i = 0; i < 4; i++)
{
Point2 <double> p = neighbourPoints[i];
if (missingElevations.ContainsValue(p))
{
MissingElevation me2 = missingElevations.Keys[missingElevations.IndexOfValue(p)];
missingElevations.Remove(me2);
me2.MissingNeighbours--;
missingElevations.Add(me2, p);
}
}
}
return(output);
}
