public GRIB2DataRepresentationSection(FileStream fs)
{
_sectionHeader = new GRIB2SectionHeader(fs);
_dataPoints = GribNumberHelper.Int4(fs);
_dataTemplate = (int)GribNumberHelper.Uint2(fs);
SetOtherAttributeByDataTemplateNo(fs);
}
public GRIB2DataRepresentationSection(FileStream fs)
{
long position = fs.Position;
_sectionHeader = new GRIB2SectionHeader(fs);
_dataPoints = GribNumberHelper.Int4(fs);
_dataTemplate = (int)GribNumberHelper.Uint2(fs);
SetOtherAttributeByDataTemplateNo(fs);
fs.Seek(position + _sectionHeader.SectionLength, SeekOrigin.Begin);
}
private void AdjustAttributes(byte[] array)
{
if (this.Resolution == 128)
{
_dx = (double)GribNumberHelper.Uint2(array[23], array[24]) / 1000.0;
if (this.GridType == 4)
{
_np = GribNumberHelper.Uint2(array[25], array[26]);
_dy = (double)_np / 1000.0;
}
else
{
_dy = (double)GribNumberHelper.Uint2(array[25], array[26]) / 1000.0;
}
_scanMode = Convert.ToInt32(array[27]);
}
else
{
_dx = (_lonEndPoint - _lonFirstPoint) / (double)(_nx - 1);
_dy = (_latEndPoint - _latFirstPoint) / (double)(_ny - 1);
}
if ((_scanMode & 128) != 0)
{
_xReverse = true;
}
if (_latEndPoint < _latFirstPoint)
{
_yReverse = true;
}
if (_thinnedGrid)
{
_thinnedXNums = new int[_ny];
_thinnedGridNum = 0;
for (int i = 0; i < _ny; i++)
{
_thinnedXNums[i] = GribNumberHelper.Int2(array[32 + i * 2], array[33 + i * 2]);
_thinnedGridNum += this.ThinnedXNums[i];
if (i == 0)
{
_nx = this.ThinnedXNums[i];
}
else
{
if (_nx < this.ThinnedXNums[i])
{
//取格点数最多那行的格点数为宽
_nx = this.ThinnedXNums[i];
}
}
}
_dx = Math.Abs(_lonEndPoint - _lonFirstPoint) / (double)(_nx - 1);
}
}
private void SetOtherAttribute(FileStream fs)
{
if (_gridType != 50)
{
// Nx - 沿x轴的点数量
_nx = GribNumberHelper.Uint2(fs);// GribNumberHelper.Int2(fs);
_nx = (_nx == -1) ? 1 : _nx;
if (_nx >= 65535)
{
_thinnedGrid = true;
}
// Ny - 沿y轴的点数量
_ny = GribNumberHelper.Uint2(fs); // GribNumberHelper.Int2(fs);
_ny = (_ny == -1) ? 1 : _ny;
_latFirstPoint = GribNumberHelper.Int3(fs) / 1000.0; // La1 - 第一个格网点的纬度
_lonFirstPoint = GribNumberHelper.Int3(fs) / 1000.0; // Lo1 - 第一个格网点的经度
_resolution = fs.ReadByte(); //分辨率和组件标识
}
switch (_gridType)
{
// Latitude/Longitude grids,Arakawa semi-staggered e-grid rotated
// Arakawa filled e-grid rotated
case 0: // Latitude/longitude grid
case 4: //Gaussian latitude/longitude grid
case 40:
case 201:
case 202:
{
_latEndPoint = GribNumberHelper.Int3(fs) / 1000.0; // La2 - 最后的格网点的纬度
_lonEndPoint = GribNumberHelper.Int3(fs) / 1000.0; // Lo2 - 最后的格网点的经度
_dx = GribNumberHelper.Int2(fs) / 1000.0; // Dx - 经度方向增加量
if (_gridType == 4)
{
_np = GribNumberHelper.Int2(fs); // Np-极点与赤道间的纬度圈数
}
else
{
_dy = GribNumberHelper.Int2(fs) / 1000.0; // Dy - 纬度方向增加量
}
_scanMode = fs.ReadByte(); //扫描模式
//29-32 reserved
fs.Seek(4, SeekOrigin.Current);
if (_sectionLength > 32)
{
// Vertical coordinates (NV) and thinned grids (PL) not supported - skip this
fs.Seek(_sectionLength - 32, SeekOrigin.Current);
}
break;
}
//Mercator projection
case 1:
_latEndPoint = GribNumberHelper.Int3(fs) / 1000.0; // La2 - 最后格网点的纬度
_lonEndPoint = GribNumberHelper.Int3(fs) / 1000.0; // Lo2 - 最后格网点的经度
// octets 24-26 (Latin - latitude where cylinder intersects the earth
_latin1 = GribNumberHelper.Int3(fs) / 1000.0; // Latin -圆柱体与地球相交处的高程
fs.ReadByte();
_scanMode = fs.ReadByte(); //扫描模式
_dx = GribNumberHelper.Int3(fs); // Dx - 经度方向增加量
_dy = GribNumberHelper.Int3(fs); // Dy - 纬度方向增加量
fs.Seek(4, SeekOrigin.Current);
if (_sectionLength > 42)
{
// Vertical coordinates (NV) and thinned grids (PL) not supported - skip this
fs.Seek(_sectionLength - 42, SeekOrigin.Current);
}
break;
//Lambert conformal, secant or tangent, conic or bi-polar, projection
case 3:
// Lov - Orientation of the grid - east lon parallel to y axis)
_lov = GribNumberHelper.Int3(fs) / 1000.0;
_dx = GribNumberHelper.Int3(fs); // Dx - X方向格网长度
_dy = GribNumberHelper.Int3(fs); // Dy - Y方向格网长度
_projetcenter = fs.ReadByte(); //投影中心标识
_scanMode = fs.ReadByte(); //扫描模式
// Latin1 - first lat where secant cone cuts spherical earth
_latin1 = GribNumberHelper.Int3(fs) / 1000.0;
// Latin2 - second lat where secant cone cuts spherical earth)
_latin2 = GribNumberHelper.Int3(fs) / 1000.0;
_latsp = GribNumberHelper.Int3(fs) / 1000.0; //南极点纬度
_lonsp = GribNumberHelper.Int3(fs) / 1000.0; //南极点经度
fs.Seek(2, SeekOrigin.Current);
if (_sectionLength > 42)
{
// Vertical coordinates (NV) and thinned grids (PL) not supported - skip this
fs.Seek(_sectionLength - 42, SeekOrigin.Current);
}
break;
case 5:
// Lov - Orientation of the grid - east lon parallel to y axis)
_lov = GribNumberHelper.Int3(fs) / 1000.0;
_dx = GribNumberHelper.Int3(fs); // Dx - 经度方向增加量
_dy = GribNumberHelper.Int3(fs); // Dy - 纬度方向增加量
_projetcenter = fs.ReadByte(); //投影中心标识
_scanMode = fs.ReadByte(); //扫描模式
fs.Seek(4, SeekOrigin.Current);
if (_sectionLength > 32)
{
// Vertical coordinates (NV) and thinned grids (PL) not supported - skip this
fs.Seek(_sectionLength - 32, SeekOrigin.Current);
}
break;
default:
break;
}
if ((_scanMode & 63) != 0)
{
throw new Exception("GDS: This scanning mode (" + _scanMode + ") is not supported.");
}
fs.Seek(_position, SeekOrigin.Begin);
byte[] array = new byte[_sectionLength];
fs.Read(array, 0, _sectionLength);
AdjustAttributes(array);
}
