探测地球云层分布的CloudSat和CALIPSO卫星
http://www.nasa.gov/mission_pages/calipso/main/index.html
http://www.nasa.gov/topics/earth/features/calipso-1billion.html
Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO)
The occasion was on CALIPSO's 9,491st orbit of Earth. Since its launch, on April 23, 2006, the satellite has traveled 260,198,685.3 miles. It has generated data that would fill almost 3,500 DVDs or more than 24,000 CDs, delighting scientists and researchers from 35 countries who are using the information to prove any number of theories about the atmosphere, about weather, about the past and how it will relate to the future.
数据格式
读取代码：
1 double lonFrom = 0; 2 double latFrom = 0; 3 double lonTo = 0; 4 double latTo = 0; 5 OSGeo.GDAL.Gdal.AllRegister(); 6 Gdal.SetConfigOption("GDAL_FILENAME_IS_UTF8", "Yes"); 7 string path = string.Format(@"C:UsersDesktoplidar_track_imageCAL_LID_L1-ValStage1-V3-02.2013-01-01T18-30-59ZN_Subset.hdf", WorldSettings.StartupDirectory); 8 //path = string.Format(@"{0}dataCAL_LID_L1-ValStage1-V3-02.2013-01-01T18-30-59ZN_Subset.hdf", WorldSettings.StartupDirectory); 9 byte[] pathUtf16 = Encoding.Unicode.GetBytes(path); 10 11 byte[] byteUtf8 = Encoding.Convert(Encoding.Unicode, Encoding.UTF8, pathUtf16); 12 13 string pathUtf8 = Encoding.UTF8.GetString(byteUtf8); 14 15 Encoding encoud = Encoding.GetEncoding(936); 16 byte[] byteGb2312 = Encoding.Convert(Encoding.Unicode, encoud, pathUtf16); 17 string pathGb2312 = encoud.GetString(byteGb2312); 18 19 if (!File.Exists(path)) 20 { 21 MessageBox.Show("Calpso数据不存在", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information); 22 return; 23 } 24 //读取文件，获取子数据集信息 25 Dataset ds = Gdal.Open(path, Access.GA_ReadOnly); 26 string[] stMetadata = ds.GetMetadata(""); 27 string[] strMetadata = ds.GetMetadata("SUBDATASETS"); 28 string info = string.Empty; 29 for (int i = 0; i < strMetadata.Length; i++) 30 { 31 info += strMetadata[i] + " "; 32 } 33 info += "读取波段数据:---------------- "; 34 //纬度数据 35 string tmpstr = strMetadata[0]; 36 tmpstr = tmpstr.Substring(tmpstr.IndexOf("=") + 1); 37 Dataset dsLat = Gdal.Open(tmpstr, Access.GA_ReadOnly); 38 string strMetadata2 = dsLat.GetDescription(); 39 40 info += string.Format("像素数目：{0} X {1}", dsLat.RasterXSize, dsLat.RasterYSize); 41 int count = dsLat.RasterCount; 42 Band bandLat = dsLat.GetRasterBand(1); 43 int Cols = dsLat.RasterXSize; 44 int Rows = dsLat.RasterYSize; 45 int width = dsLat.RasterXSize; 46 int height = dsLat.RasterYSize; 47 double min, max, no; 48 int hasvalue; 49 info += string.Format("类型Lat：{0} ", bandLat.DataType); 50 if (bandLat.DataType == DataType.GDT_Float32) 51 { 52 bandLat.GetMaximum(out max, out hasvalue); 53 bandLat.GetMinimum(out min, out hasvalue); 54 bandLat.GetNoDataValue(out no, out hasvalue); 55 float[] data = new float[Cols * Rows]; 56 bandLat.ReadRaster(0, 0, width, height, data, Cols, Rows, 0, 0); 57 58 string ddd = string.Empty; 59 double min1, max1, mean, hasvalue1; 60 OSGeo.GDAL.Gdal.GDALProgressFuncDelegate dele = new Gdal.GDALProgressFuncDelegate(GDALProgressFunc); 61 bandLat.ComputeStatistics(false, out min1, out max1, out hasvalue1, out mean, dele, ddd); 62 lonFrom = data[0]; 63 lonTo = data[data.Length - 1]; 64 } 65 //经度数据 66 string tmpstrLon = strMetadata[2]; 67 tmpstrLon = tmpstrLon.Substring(tmpstrLon.IndexOf("=") + 1); 68 Dataset dsLon = Gdal.Open(tmpstrLon, Access.GA_ReadOnly); 69 info += string.Format("像素数目：{0} X {1}", dsLon.RasterXSize, dsLon.RasterYSize); 70 Band bandLon = dsLon.GetRasterBand(1); 71 int Cols2 = dsLon.RasterXSize; 72 int Rows2 = dsLon.RasterYSize; 73 int width2 = dsLon.RasterXSize; 74 int height2 = dsLon.RasterYSize; 75 double min2, max2, no2; 76 int hasvalue2; 77 info += string.Format("类型Lon：{0} ", bandLon.DataType); 78 if (bandLon.DataType == DataType.GDT_Float32) 79 { 80 bandLon.GetMaximum(out max2, out hasvalue2); 81 bandLon.GetMinimum(out min2, out hasvalue2); 82 bandLon.GetNoDataValue(out no2, out hasvalue2); 83 float[] data2 = new float[Cols2 * Rows2]; 84 bandLon.ReadRaster(0, 0, width2, height2, data2, Cols2, Rows2, 0, 0); 85 86 string ddd = string.Empty; 87 double min1, max1, mean, hasvalue1; 88 OSGeo.GDAL.Gdal.GDALProgressFuncDelegate dele = new Gdal.GDALProgressFuncDelegate(GDALProgressFunc); 89 bandLon.ComputeStatistics(false, out min1, out max1, out hasvalue1, out mean, dele, ddd); 90 latFrom = data2[0]; 91 latTo = data2[data2.Length - 1]; 92 } 93 //读取雷达衰减系数 94 string tmpStrBackScatter = strMetadata[70]; 95 tmpStrBackScatter = tmpStrBackScatter.Substring(tmpStrBackScatter.IndexOf("=") + 1); 96 Dataset dsBackScatter = Gdal.Open(tmpStrBackScatter, Access.GA_ReadOnly); 97 info += string.Format("像素数目：{0} X {1}", dsBackScatter.RasterXSize, dsBackScatter.RasterYSize); 98 Band bandBackScatter = dsBackScatter.GetRasterBand(1); 99 int ColsBackScatter = dsBackScatter.RasterXSize; 100 int RowsBackScatter = 3000;// ds270.RasterYSize;读取3000个像素 101 int widthBackScatter = dsBackScatter.RasterXSize; 102 int heightBackScatter = 3000;// ds270.RasterYSize; 103 double min270, max270, no270; 104 int hasvalue270; 105 info += string.Format("类型衰减系数：{0} ", bandBackScatter.DataType); 106 if (bandBackScatter.DataType == DataType.GDT_Float32) 107 { 108 bandBackScatter.GetMaximum(out max270, out hasvalue270); 109 bandBackScatter.GetMinimum(out min270, out hasvalue270); 110 bandBackScatter.GetNoDataValue(out no270, out hasvalue270); 111 string ddd = string.Empty; 112 double mean, has; 113 114 OSGeo.GDAL.Gdal.GDALProgressFuncDelegate dele = new Gdal.GDALProgressFuncDelegate(GDALProgressFunc); 115 bandBackScatter.ComputeStatistics(false, out min270, out max270, out has, out mean, dele, ddd); 116 float[] data270 = new float[ColsBackScatter * RowsBackScatter]; 117 bandBackScatter.ReadRaster(0, 0, widthBackScatter, heightBackScatter, data270, ColsBackScatter, RowsBackScatter, 0, 0); 118 119 int x1width = heightBackScatter; 120 int y1height = widthBackScatter;//583 121 Bitmap bitmap = new Bitmap(x1width, y1height, System.Drawing.Imaging.PixelFormat.Format32bppArgb); 122 int iPixelSize = 4; 123 124 CreateColorRamp createColorRamp = CreateColorRamps(); 125 BitmapData bitmapdata = bitmap.LockBits(new Rectangle(0, 0, x1width, y1height), ImageLockMode.ReadWrite, bitmap.PixelFormat); 126 try 127 { 128 unsafe 129 { 130 for (int y = 0; y < y1height; y++) 131 { 132 byte* row = (byte*)bitmapdata.Scan0 + (y * bitmapdata.Stride); 133 134 for (int x = 0; x < x1width; x++) 135 { 136 //int posSrc = x + y * x1width; 137 int posSrc = y + x * y1height;//图像顺时针旋转90度 138 double item = data270[posSrc]; 139 if (item == no270) 140 { 141 Color? getColor = getColor = createColorRamp.GetColor(0); ; 142 row[x * iPixelSize] = (byte)getColor.Value.B; 143 row[x * iPixelSize + 1] = (byte)getColor.Value.G; 144 row[x * iPixelSize + 2] = (byte)getColor.Value.R; 145 row[x * iPixelSize + 3] = getColor.Value.A; 146 } 147 else 148 { 149 Color? getColor = null; 150 if (item < 0.0001 || item > 0.1) 151 { 152 getColor = createColorRamp.GetColor(0); 153 } 154 else 155 { 156 getColor = createColorRamp.GetColor(item); 157 } 158 if (getColor != null) 159 { 160 row[x * iPixelSize] = getColor.Value.B; 161 row[x * iPixelSize + 1] = getColor.Value.G; 162 row[x * iPixelSize + 2] = getColor.Value.R; 163 row[x * iPixelSize + 3] = getColor.Value.A; 164 } 165 } 166 } 167 } 168 } 169 } 170 catch 171 { 172 } 173 finally 174 { 175 bitmap.UnlockBits(bitmapdata); 176 } 177 bitmap.Save("D:\b.png"); 178 Vector3d v1 = new Vector3d(lonFrom, latFrom, 0); 179 Vector3d v2 = new Vector3d(lonTo, latTo, 0); 180 Vector3d dir = v2 - v1; 181 182 Vector3d v3 = v1 + (double)heightBackScatter / dsBackScatter.RasterYSize * dir.Normalize(); 183 CalpsoRenderObject obj = new CalpsoRenderObject("", v1, v3); 184 }
1 public CreateColorRamp CreateColorRamps()
2 {
3 CreateColorRamp createColorRamp = new CreateColorRamp();
4 List<ColorRamp> mColorRamp = new List<ColorRamp>();
5 double[] valueGray = new double[35] {0.0, 0.0001,0.0002,0.0003,0.0004,0.0005,
6 0.0006,0.0007,0.0008,0.0009,0.001,
7 0.0015,0.002, 0.0025,0.003, 0.0035,
8 0.004, 0.0045,0.005, 0.0055, 0.006,
9 0.0065,0.007, 0.0075,0.008, 0.01,
10 0.02, 0.03, 0.04, 0.05, 0.06,
11 0.07, 0.08, 0.09, 0.1};
12 int[] Rv = new int[35] {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
13 255,255,255,255,255,255,255,255,255,255,
14 70,100,130,155,180,220,225,235,240,242,
15 245,249,253,255};
16 int[] Gv = new int[35] {43,43,43,128,170,213,255,255,255,128,
17 170,255,255,213,170,128,85,0,43,85,128,
18 70,100,130,155,180,220,225,235,240,242,
19 245,249,253,255};
20 int[] Bv = new int[35] {128,170,170,255,255,255,255,213,170,128,
21 85,0,0,0,0,0,0,0,85,128,170,
22 70,100,130,155,180, 220,225,235,240,242,
23 245,249,253,255};
24
25 for (int i = 0; i < 35; i++)
26 {
27 ColorRamp clr = new ColorRamp();
28 clr.start = valueGray[i];
29 if (i < 34)
30 {
31 clr.end = valueGray[i + 1];
32 }
33 clr.ColorS = Color.FromArgb(255, Rv[i], Gv[i], Bv[i]);
34 mColorRamp.Add(clr);
35 }
36 mColorRamp[mColorRamp.Count - 1].end = 100;
37 createColorRamp.ColorRampCollection = mColorRamp;
38 return createColorRamp;
39 }
40 int GDALProgressFunc(double Complete, IntPtr Message, IntPtr Data)
41 {
42 return 1;
43 }
1 public class ColorRamp
2 {
3 public double start;
4 public double Interval;
5 public double end;
6
7 public Color ColorS;
8 }
9 public class CreateColorRamp
10 {
11 public List<ColorRamp> ColorRampCollection { get; set; }
12 public Color? GetColor(double val)
13 {
14 if (ColorRampCollection == null)
15 {
16 throw new ArgumentNullException("颜色分级设置为空");
17 }
18 for (int i = 0; i < ColorRampCollection.Count; i++)
19 {
20 ColorRamp colorRam = ColorRampCollection[i];
21 if (val >= colorRam.start && val < colorRam.end)
22 {
23 return colorRam.ColorS;
24 }
25 }
26 return null;
27
28 }
29 }
30 }
GDAL C#封装还是没有解决中文字符的问题。C# 采用Unicode，GDAL的Dll采用多字节字符。所以只能在C++的代码中做些工作，将Unicode转换为多字节字符或者是Utf8。准备测试一下。
NASA上的图片：
