/// <summary>
/// Creates a new raster with the specified cell size. If the cell size
/// is zero, this will default to the shorter of the width or height
/// divided by 256. If the cell size produces a raster that is greater
/// than 8,000 pixels in either dimension, it will be re-sized to
/// create an 8,000 length or width raster.
/// </summary>
/// <param name="fs">The featureset to convert to a raster</param>
/// <param name="cellSize">The double extent of the cell.</param>
/// <param name="fieldName">The integer field index of the file.</param>
/// <param name="destFilename">The filename of the raster to create</param>
/// <param name="driverCode">The optional GDAL driver code to use if using GDAL
/// for a format that is not discernable from the file extension. An empty string
/// is usually perfectly acceptable here.</param>
/// <param name="options">For GDAL rasters, they can be created with optional parameters
/// passed in as a string array. In most cases an empty string is perfectly acceptable.</param>
/// <param name="progressHandler">An interface for handling the progress messages.</param>
/// <returns>Generates a raster from the vectors.</returns>
public static IRaster ToRaster(IFeatureSet fs, ref double cellSize, string fieldName, string destFilename, string driverCode, string[] options, IProgressHandler progressHandler)
{
IEnvelope env = fs.Envelope;
if(cellSize == 0)
{
if(fs.Envelope.Width < fs.Envelope.Height)
{
cellSize = env.Width/256;
}
else
{
cellSize = env.Height/256;
}
}
int w = (int)Math.Ceiling(env.Width/cellSize);
if (w > 8000)
{
w = 8000;
cellSize = env.Width/8000;
}
int h = (int) Math.Ceiling(env.Height/cellSize);
if (h > 8000)
{
cellSize = env.Height/8000;
h = 8000;
}
Bitmap bmp = new Bitmap(w, h);
Graphics g = Graphics.FromImage(bmp);
g.Clear(Color.Transparent);
g.SmoothingMode = SmoothingMode.None;
g.TextRenderingHint = TextRenderingHint.SingleBitPerPixel;
g.InterpolationMode = InterpolationMode.NearestNeighbor;
Hashtable colorTable;
MapArgs args = new MapArgs(new Rectangle(0, 0, w, h), env, g);
switch (fs.FeatureType)
{
case FeatureTypes.Polygon:
{
MapPolygonLayer mpl = new MapPolygonLayer(fs);
PolygonScheme ps = new PolygonScheme();
colorTable = ps.GenerateUniqueColors(fs, fieldName);
mpl.Symbology = ps;
mpl.DrawRegions(args, new List<IEnvelope> {env});
}
break;
case FeatureTypes.Line:
{
MapLineLayer mpl = new MapLineLayer(fs);
LineScheme ps = new LineScheme();
colorTable = ps.GenerateUniqueColors(fs, fieldName);
mpl.Symbology = ps;
mpl.DrawRegions(args, new List<IEnvelope> { env });
}
break;
default:
{
MapPointLayer mpl = new MapPointLayer(fs);
PointScheme ps = new PointScheme();
colorTable = ps.GenerateUniqueColors(fs, fieldName);
mpl.Symbology = ps;
mpl.DrawRegions(args, new List<IEnvelope> { env });
}
break;
}
Type tp = fieldName == "FID" ? typeof(int) : fs.DataTable.Columns[fieldName].DataType;
if (tp == typeof(string)) tp = typeof (double); // We will try to convert to double if it is a string
Raster output = new Raster();
MWImageData image = new MWImageData(bmp, env);
ProgressMeter pm = new ProgressMeter(progressHandler, "Converting To Raster Cells", h);
output.CreateNew(destFilename, driverCode, w, h, 1, tp, options);
output.Bounds = new RasterBounds(h, w, env);
List<RcIndex> locations = new List<RcIndex>();
List<string> failureList = new List<string>();
for (int row = 0; row < h; row++)
{
for (int col = 0; col < w; col++)
{
Color c = image.GetColor(row, col);
if (c.A == 0)
{
output.Value[row, col] = output.NoDataValue;
}
else
{
if (colorTable.ContainsKey(c) == false)
{
if (c.A < 125)
{
output.Value[row, col] = output.NoDataValue;
continue;
}
// Use a color matching distance to pick the closest member
object val = GetCellValue(w, h, row, col, image, c, colorTable, locations);
output.Value[row, col] = GetDouble(val, failureList);
}
else
{
output.Value[row, col] = GetDouble(colorTable[c], failureList);
}
}
}
pm.CurrentValue = row;
}
const int maxIterations = 5;
int iteration = 0;
while(locations.Count > 0)
{
List<RcIndex> newLocations = new List<RcIndex>();
foreach (RcIndex location in locations)
{
object val = GetCellValue(w, h, location.Row, location.Column, image, image.GetColor(location.Row, location.Column), colorTable, newLocations);
output.Value[location.Row, location.Column] = GetDouble(val, failureList);
}
locations = newLocations;
iteration++;
if(iteration > maxIterations) break;
}
pm.Reset();
return output;
}
private static object GetCellValue(int w, int h, int row, int col, MWImageData image, Color c, Hashtable colorTable, List<RcIndex> locations)
{
double dmin = double.MaxValue;
object val = 0;
bool empty = true;
// Search 8 neighbor cells for likely blended neighbors
// (otherwise distant shapes might match better incorrectly)
for (int i = -1; i < 2; i++)
{
for (int j = -1; j < 2; j++)
{
if (i == j && j == 0) continue;
if (row + i < 0 || row + i >= h) continue;
if (col + j < 0 || col + j >= w) continue;
Color nc = image.GetColor(row + i, col + j);
if (colorTable.ContainsKey(nc) == false) continue;
double d = (nc.R - c.R) * (nc.R - c.R) + (nc.G - c.G) * (nc.G - c.G) +
(nc.B - c.B) * (nc.B - c.B);
if (d >= dmin) continue;
val = colorTable[nc];
dmin = d;
empty = false;
image.SetColor(row, col, nc);
}
}
if (empty)
{
locations.Add(new RcIndex(row, col));
}
return val;
}