public static async Task <GeoReferencedImage> Create(List <ISqlGeometryAware> points, Func <ISqlGeometryAware, double> valueFunc, int width, int height, DiscreteRangeColor ranges, double?maxDistance)
{
return(await Task.Run <GeoReferencedImage>(() =>
{
var boundingBox = SqlGeometryExtensions.GetBoundingBox(points.Select(p => p.TheSqlGeometry).ToList());
//scale
var scaleX = width / boundingBox.Width;
var scaleY = height / boundingBox.Height;
var scale = Math.Min(scaleX, scaleY);
width = (int)(scale *boundingBox.Width);
height = (int)(scale *boundingBox.Height);
//create empty raster
Bitmap result = new Bitmap(width, height);
List <Point3D> pointSet = points.Select(p => new Point3D(p.TheSqlGeometry.STX.Value, p.TheSqlGeometry.STY.Value, valueFunc(p))).ToList();
var maxValue = pointSet.Max(p => p.Z);
var minValue = pointSet.Min(p => p.Z);
var rangeValue = maxValue - minValue;
var midValue = rangeValue / 2.0 + minValue;
//ContinousRangeColor ranges = new ContinousRangeColor(values, colors);
//DiscreteRangeColor ranges = new DiscreteRangeColor(values, colors);
var stopwatch = System.Diagnostics.Stopwatch.StartNew();
for (int i = 0; i < height; i++)
{
for (int j = 0; j < width; j++)
{
var x = boundingBox.XMin + j / scale;
var y = boundingBox.YMax - i / scale;
var value = IRI.Msh.Common.Analysis.Interpolation.Idw.Calculate(pointSet, new Msh.Common.Primitives.Point(x, y), maxDistance);
if (value.HasValue)
{
try
{
result.SetPixel(j, i + 0, ranges.Interpolate(value.Value));
}
catch (Exception ex)
{
}
}
else
{
//result.SetPixel(j, i, Color.Transparent);
}
}
}
stopwatch.Stop();
var ellapsedtime = stopwatch.ElapsedMilliseconds;
stopwatch.Restart();
return new GeoReferencedImage(ImageUtility.AsByteArray(result), boundingBox.Transform(IRI.Msh.CoordinateSystem.MapProjection.MapProjects.WebMercatorToGeodeticWgs84));
}));
}