help()

void datrw::su::SUheader::help ( std::ostream &  os )

static

print online help regarding header fields and TOAST data

Definition at line 548 of file suheader.cc.

Referenced by datrw::isustream::help(), and datrw::osustream::help().

    {
      os <<
        "The library uses only few header fields. Upon reading the\n"
        "following fields are used:\n";
      os <<
        "wid2.nsamples = header.ns\n"
        "wid2.dt       = header.dt*1.e-6\n"
        "wid2.date     = srce.date+header.delrt*1.e-3\n"
        "wid2.channel  = header.tracf\n"
        "                (tracf = Trace number within original field record)\n"
        "wid2.station  = header.tracf\n"
        "wid2.auxid    = header.fldr\n"
        "                (fldr = Original field record number)\n";
      os <<
        "info.cx       = header.gx*scalcof\n"
        "info.cy       = header.gy*scalcof\n"
        "info.cz       = header.gelev*scalelf\n"
        "info.nstacks  = header.nvs\n";
      os <<
        "srce.cx       = header.sx*scalcof\n"
        "srce.cy       = header.sy*scalcof\n"
        "srce.cz       = header.sdepth*scalelf\n"
        "srce.date     = date(year,day,hour,minute,sec)\n";
      os <<
        "header.scalco and header.scalel are as defined for the SEG-Y "
        "format:\n"
        "http://www.seg.org/SEGportalWEBproject/prod/SEG-Publications/Pub-Technical-Standards/Documents/seg_y_rev1.pdf\n"
        "except when their modulus is smaller than 10 and larger than 0.\n"
        "In this case the scaling factors scalcof and scalelf are taken to be\n"
        "10 to the power of header.scalco or header.scalel, respectively\n";
      os <<
        "Notice that in contrast to the definition of the SeismicUn*x format\n"
        "this library also supports high frequency sampling for ultrasonic\n"
        "data. A special meaning of header fields was defined within the TOAST\n"
        "project:\n";
      os <<
        "Small sampling interval (smaller than 1 microsecond) as used in\n"
        "ultrasonic recordings are to be stored in SeismicUn*x data format\n"
        "within TOAST as follows:\n";
      os <<
        "1. Time values for ultrasonic data will be given in nanoseconds for\n"
        "   dt and microseconds for delrt.\n"
        "2. This applies to fields\n"
        "   a) dt (byte# 117-118): sample interval\n"
        "   b) delrt (byte# 109-110): delay recording time\n";
      os <<
        "3. Time units other than microseconds or nanoseconds for dt and\n"
        "   milliseconds or microseconds for delrt are not allowed.\n"
        "4. Field d1 (byte# 181-184) in TOAST data will be\n"
        "   a) either zero, indicating standard seismic data with a\n"
        "      micro seconds time scale or\n"
        "   b) provide the sampling interval in seconds, thus indicating\n"
        "      i)  either standard seismic data, if d1 in seconds matches\n"
        "          dt if the latter is taken in microseconds or\n"
        "      ii) ultrasonic data, if d1 in seconds matches dt if the\n"
        "          latter is taken in nanoseconds and delrt is taken\n"
        "          in microseconds\n";
      os <<
        "This way it is possible to use SU tools to sort traces or similar\n"
        "or even waveform filters. The user just has to take care to pass\n"
        "filter frequencies in kHz rather than Hz in the case of ultrasonic\n"
        "data.\n";
    } // void SUheader::help(std::ostream& os) const

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