//绘制矢量图层
private void DrawShpLayer(Graphics g, MapLayer curLayer, int index)
{
Ogr.RegisterAll();
OSGeo.GDAL.Gdal.SetConfigOption("GDAL_DATA", @".\gdal\data");
DataSource ds = Ogr.Open(curLayer.FilePath, 0);
//遍历每个图层
for (int i = 0; i < ds.GetLayerCount(); i++)
{
Layer layer = ds.GetLayerByIndex(i);
Feature feature;
//遍历图层中每个要素
int fid = 0;
while ((feature = layer.GetNextFeature()) != null)
{
Geometry geom = feature.GetGeometryRef();
if (geom != null)
{
string type = geom.GetGeometryName();
if (type == "POLYGON")
{
DrawPolygon(g, geom, index);
}
else if (type == "MULTIPOLYGON")
{
DrawMultiPolygon(g, geom, index);
}
else if (type == "POINT")
{
DrawPoint(g, geom, index, fid);
}
++fid;
}
}
}
ds.FlushCache();
ds.Dispose();
}
//绘制tiff图层
private void DrawTiffLayer(Graphics g, MapLayer curLayer, int index)
{
//PictureBox pictureBox = new PictureBox();
float[] MBR = new float[4];
curLayer.GetExtent(MBR);
int width, height;
//根据比例尺确定图片大小和位置
PointF locationPoint = FromMapPoint(new PointF(MBR[0], MBR[3]));
if (locationPoint.Y < this.Height && locationPoint.X < this.Width)
{
width = (int)((MBR[2] - MBR[0]) / _DisplayScale);
height = (int)((MBR[3] - MBR[1]) / _DisplayScale);
Dataset ds = Gdal.Open(curLayer.FilePath, Access.GA_ReadOnly);
int imgWidth = ds.RasterXSize;
int imgHeight = ds.RasterYSize;
float[] r = new float[width * height];
Band band = ds.GetRasterBand(1);
band.ReadRaster(0, 0, imgWidth, imgHeight, r, width, height, 0, 0);
//获取NoData值
double nodata;
int handle = 1;
band.GetNoDataValue(out nodata, out handle);
double[] MinMax = { 0, 0 };
band.ComputeRasterMinMax(MinMax, 0);
int i, j;
Color newColor = Color.Transparent;
for (i = 0; i < width; i++)
{
for (j = 0; j < height; j++)
{
float value = r[i + j * width]; //像元值
if (value > nodata + 1)
{
if (MapLayers[index].Style.Styles.Count == 0)
{
int value1 = 0;
if (MinMax[0] < -300)//DEM数据拉伸
{
if (value >= -128)
{
value1 = (int)((value + 128) / (MinMax[1] + 128) * 205.0 + 50);
}
}
else
{
value1 = (int)((value - MinMax[0]) / (MinMax[1] - MinMax[0]) * 235.0 + 20);
}
newColor = Color.FromArgb(value1, value1, value1);
}
else if (MapLayers[index].Style.Styles[0].Rules[0].RasterSymbol.ColorMap.Count == 0)
{
int value1 = 0;
if (MinMax[0] < -300)//DEM数据拉伸
{
if (value >= -128)
{
value1 = (int)((value + 128) / (MinMax[1] + 128) * 205.0 + 50);
}
}
else
{
value1 = (int)((value - MinMax[0]) / (MinMax[1] - MinMax[0]) * 235.0 + 20);
}
newColor = Color.FromArgb(value1, value1, value1);
newColor = Color.FromArgb(Convert.ToInt32(255 * curLayer.Style.Styles[0].Rules[0].RasterSymbol.Opacity), newColor);
}
else // 按照Style绘制
{
for (int eCount = 0; eCount < curLayer.Style.Styles[0].Rules[0].RasterSymbol.ColorMap.Count - 1; ++eCount)
{
if (value >= curLayer.Style.Styles[0].Rules[0].RasterSymbol.ColorMap[eCount].Quantity &&
value <= curLayer.Style.Styles[0].Rules[0].RasterSymbol.ColorMap[eCount + 1].Quantity)
{
newColor = Color.FromArgb(Convert.ToInt32(255 * curLayer.Style.Styles[0].Rules[0].RasterSymbol.ColorMap[eCount].Opacity),
ColorTranslator.FromHtml(curLayer.Style.Styles[0].Rules[0].RasterSymbol.ColorMap[eCount].Color));
break;
}
}
}
}
g.FillRectangle(new SolidBrush(newColor), new RectangleF(locationPoint.X + i, locationPoint.Y + j, 1, 1));
}
}
ds.FlushCache();
ds.Dispose();
}
}
