private float[] ReadGridPointBySimplePack(int xoffset, int yoffset, int width, int height)
{
uint val;
float[] bufRetDatas;
float num;
float num2;
bool[] bitmap;
byte[] _bufferBytes;
int numberOfBits;
float referenceValue;
GetFsValues(out bufRetDatas, out num, out num2, out bitmap, out _bufferBytes, out numberOfBits, out referenceValue);
if (bitmap == null)
{
ReadDataWithoutBitmap(xoffset, yoffset, width, height, bufRetDatas, num, num2, _bufferBytes, numberOfBits, referenceValue);
}
else
{
ReadDataWithBitmap(xoffset, yoffset, bufRetDatas, num, num2, bitmap, _bufferBytes, numberOfBits, referenceValue);
}
int scanMode = _record.GDS.ScanMode;
ScanModeApplier.ApplyScanMode(scanMode, width, ref bufRetDatas);
return(bufRetDatas);
}
public float[] Read(int xoffset, int yoffset, int width, int height)
{
try
{
if (_fileStream == null)
{
return(null);
}
if (width > _width | height > _height)
{
return(null);
}
if (_isBmsExist)
{
throw new NotSupportedException("不支持BitMapSection存在情况下的数据读取");
}
_fileStream.Seek(_dataoffset, SeekOrigin.Begin);
int sectionBytesLength = GribNumberHelper.Uint3(_fileStream); //整个区段的字节长度
int flagsAndUnusedbits = _fileStream.ReadByte();
if ((flagsAndUnusedbits & 192) != 0) //&1100,取前两位，仅支持是flag[0],flag[1]都是0的情况
{
throw new NotSupportedException("BDS: (octet 4, 1st half) not grid point data and simple packing ");
}
int unusedbits = flagsAndUnusedbits & 15; //&1111,取后四位的数值
_binScale = GribNumberHelper.Int2(_fileStream);
_refValue = ComputeReferenceValue(_fileStream); //GribNumberHelper.Float4(_fileStream);
_numBits = _fileStream.ReadByte();
if (_numBits == 0)
{
_isConstant = true;
return(null);
}
float refRenamed = (float)(Math.Pow(10.0, -_decscale) * _refValue);
float scale = (float)(Math.Pow(10.0, -_decscale) * Math.Pow(2.0, _binScale));
//long firstOffset = _fileStream.Position;
//points = new GRIB_Point[((dataLength - 11) * 8 - unusedbits) / numbits]; //当前情况下，整个数据区域的大小
var bufRetDatas = new float[height * width];
var allDataBytesLength = (int)Math.Ceiling(((sectionBytesLength - 11) * 8 - unusedbits) / 8d); //当前情况下，整个二进制数据所占用的字节数
int realDataLength = width * height * _numBits / 8 + 1;
var bufferBytes = new byte[allDataBytesLength]; //new byte[Math.Max(allDataBytesLength, realDataLength)]; //
_fileStream.Read(bufferBytes, 0, allDataBytesLength);
uint val;
using (BitStream bs = new BitStream(new MemoryStream(bufferBytes)))
{
bs.Position = 0;
if (_thinnedGrid)
{
return(ReadDataWithThinnedValue(sectionBytesLength, unusedbits, refRenamed, scale, width, height, xoffset, yoffset, bs));
}
for (int j = yoffset; j < yoffset + height; j++) //缓存数据，上下调整前的第j行
{
if (_firstlat < _lastlat) //记录方向为从南到北
{
bs.Position = ((_height - j - 1) * _width + xoffset) * _numBits; // +bitOffset;
for (int i = xoffset; i < xoffset + width; i++)
{
bs.Read(out val, 0, _numBits);
if (_firstlon == 0 && _lastlon > 300) //最大经度超过180在地图上将实际在西半球，经度为大于-180，但日本C数据最大为200°，不再分区域显示，故将界限定为300，影响X区域和Y区域的数据存储
{
int halfLon = (int)((_lastlon - _firstlon) / _xresolution);
if (i < halfLon)
{
bufRetDatas[halfLon + i + width * (j - yoffset)] = (float)Math.Round(refRenamed + scale * val, 6);
}
else
{
bufRetDatas[i - halfLon + width * (j - yoffset)] = (float)Math.Round(refRenamed + scale * val, 6);
}
}
else
{
bufRetDatas[i + width * (j - yoffset)] = (float)Math.Round(refRenamed + scale * val, 6);
}
}
}
else
{
if (j == yoffset)
{
//_fileStream.Seek((_width * yoffset + xoffset) * _numBits / 8, SeekOrigin.Current); //起始位置字节流向后偏移的位置，(_width*yoffset+xoffset)表示偏移的点个数
//numbits表示每个点的数值所占的位数，除以8表示每个点占的字节数，seek(函数以字节为单位)
bs.Position += (_width * yoffset + xoffset) * _numBits;
}
else
{
//_fileStream.Seek((_width - width) * _numBits / 8, SeekOrigin.Current);
bs.Position += (_width - width) * _numBits;
}
for (int i = xoffset; i < xoffset + width; i++)
{
bs.Read(out val, 0, _numBits);
if (_firstlon == 0 && _lastlon > 300)
{
int halfLon = (int)((_lastlon - 180 + _xresolution) / _xresolution);
if (i < halfLon)
{
bufRetDatas[halfLon + i + width * (j - yoffset)] = (float)Math.Round(refRenamed + scale * val, 6);
}
else
{
bufRetDatas[i - halfLon + width * (j - yoffset)] = (float)Math.Round(refRenamed + scale * val, 6);
}
}
else
{
bufRetDatas[i + width * (j - yoffset)] = (float)Math.Round(refRenamed + scale * val, 6);
}
}
}
}
}
ScanModeApplier.ApplyScanMode(_scanMode, width, ref bufRetDatas);
//if (_thinnedGrid)
//{
// return ReadDataWithThinnedValue(bufRetDatas, width, height);
//}
return(bufRetDatas);
}
finally
{
_fileStream.Seek(0, SeekOrigin.Begin);
}
}
private float[] ReadGridPointByComplexPack(int xOffset, int yOffset, int width, int height)
{
int mvm = _record.DRS.MissingValueManagement;
float pmv = _record.DRS.PrimaryMissingValue;
int NG = _record.DRS.NumberOfGroups;
// 6-xx Get reference values for groups (X1's)
int[] X1 = new int[NG];
int nb = _record.DRS.NumberOfBits;
_bitPos = 0;
_bitBuf = 0;
for (int i = 0; i < NG; i++)
{
X1[i] = Bits2UInt(nb, _fs);
}
// [xx +1 ]-yy Get number of bits used to encode each group
int[] NB = new int[NG];
nb = _record.DRS.BitsGroupWidths;
_bitPos = 0;
_bitBuf = 0;
for (int i = 0; i < NG; i++)
{
NB[i] = Bits2UInt(nb, _fs);
}
// [yy +1 ]-zz Get the scaled group lengths using formula
// Ln = ref + Kn * len_inc, where n = 1-NG,
// ref = referenceGroupLength, and len_inc = lengthIncrement
int[] L = new int[NG];
int countL = 0;
int ref_Renamed = _record.DRS.ReferenceGroupLength;
int len_inc = _record.DRS.LengthIncrement;
nb = _record.DRS.BitsScaledGroupLength;
_bitPos = 0;
_bitBuf = 0;
for (int i = 0; i < NG; i++)
{
// NG
L[i] = ref_Renamed + (Bits2UInt(nb, _fs) * len_inc);
countL += L[i];
}
// [zz +1 ]-nn get X2 values and calculate the results Y using formula
// Y * 10**D = R + (X1 + X2) * 2**E
int D = _record.DRS.DecimalScaleFactor;
float DD = (float)System.Math.Pow((double)10, (double)D);
float R = _record.DRS.ReferenceValue;
int E = _record.DRS.BinaryScaleFactor;
float EE = (float)System.Math.Pow((double)2.0, (double)E);
float[] data = new float[countL];
int count = 0;
int[] bitsmv1 = new int[31];
for (int i = 0; i < 31; i++)
{
bitsmv1[i] = (int)System.Math.Pow((double)2, (double)i) - 1;
}
int X2;
_bitPos = 0;
_bitBuf = 0;
for (int i = 0; i < NG - 1; i++)
{
for (int j = 0; j < L[i]; j++)
{
if (NB[i] == 0)
{
if (mvm == 0)
{
// X2 = 0
data[count++] = (R + X1[i] * EE) / DD;
}
else if (mvm == 1)
{
data[count++] = pmv;
}
}
else
{
X2 = Bits2UInt(NB[i], _fs);
if (mvm == 0)
{
data[count++] = (R + (X1[i] + X2) * EE) / DD;
}
else if (mvm == 1)
{
// X2 is also set to missing value is all bits set to 1's
if (X2 == bitsmv1[NB[i]])
{
data[count++] = pmv;
}
else
{
data[count++] = (R + (X1[i] + X2) * EE) / DD;
}
}
}
}
}
// process last group
int last = _record.DRS.LengthLastGroup;
for (int j = 0; j < last; j++)
{
// last group
if (NB[NG - 1] == 0)
{
if (mvm == 0)
{
// X2 = 0
data[count++] = (R + X1[NG - 1] * EE) / DD;
}
else if (mvm == 1)
{
data[count++] = pmv;
}
}
else
{
X2 = Bits2UInt(NB[NG - 1], _fs);
if (mvm == 0)
{
data[count++] = (R + (X1[NG - 1] + X2) * EE) / DD;
}
else if (mvm == 1)
{
// X2 is also set to missing value is all bits set to 1's
if (X2 == bitsmv1[NB[NG - 1]])
{
data[count++] = pmv;
}
else
{
data[count++] = (R + (X1[NG - 1] + X2) * EE) / DD;
}
}
}
} // end for j
int scanMode = _record.GDS.ScanMode;
ScanModeApplier.ApplyScanMode(scanMode, width, ref data);
return(data);
}
private float[] ReadGridPointByComplexPackAndSpatial(int xOffset, int yOffset, int width, int height)
{
int mvm = _record.DRS.MissingValueManagement;
float pmv = _record.DRS.PrimaryMissingValue;
int NG = _record.DRS.NumberOfGroups;
int g1 = 0, gMin = 0, h1 = 0, h2 = 0, hMin = 0;
// [6-ww] 1st values of undifferenced scaled values and minimums
int os = _record.DRS.OrderSpatial;
int ds = _record.DRS.DescriptorSpatial;
_bitPos = 0; _bitBuf = 0;
int sign;
// ds is number of bytes, convert to bits -1 for sign bit
ds = ds * 8 - 1;
if (os == 1)
{
// first order spatial differencing g1 and gMin
sign = Bits2UInt(1, _fs);
g1 = Bits2UInt(ds, _fs);
if (sign == 1)
{
g1 *= (-1);
}
sign = Bits2UInt(1, _fs);
gMin = Bits2UInt(ds, _fs);
if (sign == 1)
{
gMin *= (-1);
}
}
else if (os == 2)
{
//second order spatial differencing h1, h2, hMin
sign = Bits2UInt(1, _fs);
h1 = Bits2UInt(ds, _fs);
if (sign == 1)
{
h1 *= (-1);
}
sign = Bits2UInt(1, _fs);
h2 = Bits2UInt(ds, _fs);
if (sign == 1)
{
h2 *= (-1);
}
sign = Bits2UInt(1, _fs);
hMin = Bits2UInt(ds, _fs);
if (sign == 1)
{
hMin *= (-1);
}
}
else
{
return(null);
}
// [ww +1]-xx Get reference values for groups (X1's)
int[] X1 = new int[NG];
int nb = _record.DRS.NumberOfBits;
_bitPos = 0;
_bitBuf = 0;
for (int i = 0; i < NG; i++)
{
X1[i] = Bits2UInt(nb, _fs);
}
// [xx +1 ]-yy Get number of bits used to encode each group
int[] NB = new int[NG];
nb = _record.DRS.BitsGroupWidths;
_bitPos = 0;
_bitBuf = 0;
for (int i = 0; i < NG; i++)
{
NB[i] = Bits2UInt(nb, _fs);
}
// [yy +1 ]-zz Get the scaled group lengths using formula
// Ln = ref + Kn * len_inc, where n = 1-NG,
// ref = referenceGroupLength, and len_inc = lengthIncrement
int[] L = new int[NG];
int countL = 0;
int ref_Renamed = _record.DRS.ReferenceGroupLength;
int len_inc = _record.DRS.LengthIncrement;
nb = _record.DRS.BitsScaledGroupLength;
_bitPos = 0;
_bitBuf = 0;
for (int i = 0; i < NG; i++)
{
// NG
L[i] = ref_Renamed + (Bits2UInt(nb, _fs) * len_inc);
countL += L[i];
}
// [zz +1 ]-nn get X2 values and add X1[ i ] + X2
float[] data = new float[countL];
// used to check missing values when X2 is packed with all 1's
int[] bitsmv1 = new int[31];
for (int i = 0; i < 31; i++)
{
bitsmv1[i] = (int)System.Math.Pow((double)2, (double)i) - 1;
}
int count = 0;
int X2;
_bitPos = 0;
_bitBuf = 0;
for (int i = 0; i < NG - 1; i++)
{
for (int j = 0; j < L[i]; j++)
{
if (NB[i] == 0)
{
if (mvm == 0)
{
// X2 = 0
data[count++] = X1[i];
}
else if (mvm == 1)
{
data[count++] = pmv;
}
}
else
{
X2 = Bits2UInt(NB[i], _fs);
if (mvm == 0)
{
data[count++] = X1[i] + X2;
}
else if (mvm == 1)
{
// X2 is also set to missing value is all bits set to 1's
if (X2 == bitsmv1[NB[i]])
{
data[count++] = pmv;
}
else
{
data[count++] = X1[i] + X2;
}
}
}
}
}
// process last group
int last = _record.DRS.LengthLastGroup;
for (int j = 0; j < last; j++)
{
// last group
if (NB[NG - 1] == 0)
{
if (mvm == 0)
{
// X2 = 0
data[count++] = X1[NG - 1];
}
else if (mvm == 1)
{
data[count++] = pmv;
}
}
else
{
X2 = Bits2UInt(NB[NG - 1], _fs);
if (mvm == 0)
{
data[count++] = X1[NG - 1] + X2;
}
else if (mvm == 1)
{
// X2 is also set to missing value is all bits set to 1's
if (X2 == bitsmv1[NB[NG - 1]])
{
data[count++] = pmv;
}
else
{
data[count++] = X1[NG - 1] + X2;
}
}
}
}
if (os == 1)
{
// g1 and gMin this coding is a sort of guess, no doc
float sum = 0;
if (mvm == 0)
{
// no missing values
for (int i = 1; i < data.Length; i++)
{
data[i] += gMin; // add minimum back
}
data[0] = g1;
for (int i = 1; i < data.Length; i++)
{
sum += data[i];
data[i] = data[i - 1] + sum;
}
}
else
{
// contains missing values
float lastOne = pmv;
// add the minimum back and set g1
int idx = 0;
for (int i = 0; i < data.Length; i++)
{
if (data[i] != pmv)
{
if (idx == 0)
{
// set g1
data[i] = g1;
lastOne = data[i];
idx = i + 1;
}
else
{
data[i] += gMin;
}
}
}
if (lastOne == pmv)
{
return(data);
}
for (int i = idx; i < data.Length; i++)
{
if (data[i] != pmv)
{
sum += data[i];
data[i] = lastOne + sum;
lastOne = data[i];
}
}
}
}
else if (os == 2)
{
//h1, h2, hMin
float hDiff = h2 - h1;
float sum = 0;
if (mvm == 0)
{
// no missing values
for (int i = 2; i < data.Length; i++)
{
data[i] += hMin; // add minimum back
}
data[0] = h1;
data[1] = h2;
sum = hDiff;
for (int i = 2; i < data.Length; i++)
{
sum += data[i];
data[i] = data[i - 1] + sum;
}
}
else
{
// contains missing values
int idx = 0;
float lastOne = pmv;
// add the minimum back and set h1 and h2
for (int i = 0; i < data.Length; i++)
{
if (data[i] != pmv)
{
if (idx == 0)
{
// set h1
data[i] = h1;
sum = 0;
lastOne = data[i];
idx++;
}
else if (idx == 1)
{
// set h2
data[i] = h1 + hDiff;
sum = hDiff;
lastOne = data[i];
idx = i + 1;
}
else
{
data[i] += hMin;
}
}
}
if (lastOne == pmv)
{
return(data);
}
for (int i = idx; i < data.Length; i++)
{
if (data[i] != pmv)
{
sum += data[i];
data[i] = lastOne + sum;
lastOne = data[i];
}
}
}
} // end h1, h2, hMin
// formula used to create values, Y * 10**D = R + (X1 + X2) * 2**E
int D = _record.DRS.DecimalScaleFactor;
float DD = (float)System.Math.Pow((double)10, (double)D);
float R = _record.DRS.ReferenceValue;
int E = _record.DRS.BinaryScaleFactor;
float EE = (float)System.Math.Pow((double)2.0, (double)E);
if (mvm == 0)
{
// no missing values
for (int i = 0; i < data.Length; i++)
{
data[i] = (R + data[i] * EE) / DD;
}
}
else
{
// missing value == 1
for (int i = 0; i < data.Length; i++)
{
if (data[i] != pmv)
{
data[i] = (R + data[i] * EE) / DD;
}
}
}
int scanMode = _record.GDS.ScanMode;
ScanModeApplier.ApplyScanMode(scanMode, width, ref data);
return(data);
}