public GRIB2IdentificationSection(FileStream fs)
{
//段长度，段号
long position = fs.Position;
_sectionHeader = new GRIB2SectionHeader(fs);
if (_sectionHeader.SectionNo != 1)
{
return;
}
_centerId = GribNumberHelper.Int2(fs);
_subcenterId = GribNumberHelper.Int2(fs);
_masterTableVersionNo = fs.ReadByte();
_locationTableVersion = fs.ReadByte();
_significanceOfRT = fs.ReadByte();
int year = GribNumberHelper.Int2(fs);
int month = fs.ReadByte();
int day = fs.ReadByte();
int hour = fs.ReadByte();
int minute = fs.ReadByte();
int second = fs.ReadByte();
_referenceTime = new DateTime(year, month, day, hour, minute, second, DateTimeKind.Utc);
_productStatus = fs.ReadByte();
_productType = fs.ReadByte();
fs.Seek(position + _sectionHeader.SectionLength, SeekOrigin.Begin);
}
public GRIB2DataRepresentationSection(FileStream fs)
{
_sectionHeader = new GRIB2SectionHeader(fs);
_dataPoints = GribNumberHelper.Int4(fs);
_dataTemplate = (int)GribNumberHelper.Uint2(fs);
SetOtherAttributeByDataTemplateNo(fs);
}
private int _nb; //Number of contributing spectral bands(Template 30)
public GRIB2ProductDefinitionSection(FileStream fs)
{
_sectionHeader = new GRIB2SectionHeader(fs);
_coordinates = GribNumberHelper.Int2(fs);
_productDefinitionTemplateNo = GribNumberHelper.Int2(fs);
SetOtherAttributeByProductDefinition(fs);
}
public GRIB2DataSection(FileStream fs)
{
_sectionHeader = new GRIB2SectionHeader(fs);
if (_sectionHeader.SectionLength > 0 && _sectionHeader.SectionLength < fs.Length)
{
fs.Seek(_sectionHeader.SectionLength - 5, SeekOrigin.Current);
}
}
public GRIB2DataSection(FileStream fs, long dataOffset)
{
long position = fs.Position;
_sectionHeader = new GRIB2SectionHeader(fs);
_dataOffset = dataOffset;
_dataLength = _sectionHeader.SectionLength - 5;
fs.Seek(position + _sectionHeader.SectionLength, SeekOrigin.Begin);
}
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 int _nb; //Number of contributing spectral bands(Template 30)
public GRIB2ProductDefinitionSection(FileStream fs)
{
long position = fs.Position;
_sectionHeader = new GRIB2SectionHeader(fs);
_coordinates = GribNumberHelper.Int2(fs);
_productDefinitionTemplateNo = GribNumberHelper.Int2(fs);
SetOtherAttributeByProductDefinition(fs);
fs.Seek(position + _sectionHeader.SectionLength, SeekOrigin.Begin);
}
public GRIB2LocalUseSection(FileStream fs)
{
_sectionHeader = new GRIB2SectionHeader(fs);
if (_sectionHeader.SectionNo != 2)
{
fs.Seek(-5, SeekOrigin.Current);
return;
}
_localUse = new byte[_sectionHeader.SectionLength - 5];
fs.Read(_localUse, 0, _localUse.Length);
}
private float _dstart; //Dstart ― offset from origin to inner bound
public GRIB2GridDefinitionSection(FileStream fs)
{
_sectionHeader = new GRIB2SectionHeader(fs);
_source = fs.ReadByte();
_pointsNumber = GribNumberHelper.Int4(fs);
_olon = fs.ReadByte();
_iolon = fs.ReadByte();
_gridTemplateNo = GribNumberHelper.Int2(fs);
_gridName = GetGridNameByGridNo();
SetAttributeByGridTemplateNo(fs);
}
private float _dstart; //Dstart ― offset from origin to inner bound
public GRIB2GridDefinitionSection(FileStream fs)
{
long position = fs.Position;
_sectionHeader = new GRIB2SectionHeader(fs);
_source = fs.ReadByte();
_pointsNumber = GribNumberHelper.Int4(fs);
_olon = fs.ReadByte();
_iolon = fs.ReadByte();
_gridTemplateNo = GribNumberHelper.Int2(fs);
_gridName = GetGridNameByGridNo();
SetAttributeByGridTemplateNo(fs);
fs.Seek(position + _sectionHeader.SectionLength, SeekOrigin.Begin);
}
private bool[] _bitmap = null;//是否是位图
public GRIB2BitMapSection(FileStream fs, int numberPoints)
{
int[] bitmask = new int[] { 128, 64, 32, 16, 8, 4, 2, 1 };
_sectionHeader = new GRIB2SectionHeader(fs);
_bitMapIndicator = fs.ReadByte();
// no bitMap
if (_bitMapIndicator != 0)
{
return;
}
sbyte[] data = new sbyte[_sectionHeader.SectionLength - 6];
StreamReadHelper.ReadInput(fs, data, 0, data.Length);
// create new bit map, octet 4 contains number of unused bits at the end
_bitmap = new bool[numberPoints];
// fill bit map
for (int i = 0; i < _bitmap.Length; i++)
{
_bitmap[i] = (data[i / 8] & bitmask[i % 8]) != 0;
}
}
