[GDAL]读取HDF格式的calipso数据

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 9,491^st 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:\Users\Desktop\lidar_track_image\CAL_LID_L1-ValStage1-V3-02.2013-01-01T18-30-59ZN_Subset.hdf", WorldSettings.StartupDirectory);
  8             //path = string.Format(@"{0}\data\CAL_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] + "\n";
 32             }
 33             info += "读取波段数据:----------------\n";
 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}\n", 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}\n", 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}\n", 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             }

View Code

 

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         }

CreateColorRamp

 

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 }

View Code

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：