krischer / instaseis

Instant high-frequency seismograms from an AxiSEM database
http://instaseis.net
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SAC DIST field value is incorrect when both receiver and event lats are zero #55

Closed manoch-iris closed 7 years ago

manoch-iris commented 7 years ago

A SYNGINE user reported that:

if url is http://service.iris.edu/irisws/syngine/1/query?origintime=2017-04-15T06:30:00.000\&sourcelatitude=0\&sourcelongitude=100\&sourcedepthinmeters=20000\&sourcemomenttensor=1.04e22,-0.039e22,-1e22,0.304e22,-1.52,-0.119e22\&receiverlatitude=0\&components=ZRT\&format=saczip\&model=prem_i_2s\&units=velocity\&receiverlongitude=105 , the head parameter of dist should be about 556.599. But, the fact is 20004.3

I confirmed this and did a test and found out that if I change lat values to a non-zero value (for example 0.1), DIST field is populated correctly.

FILE: XX.S0001.SE.BXZ.sac - 1

    NPTS = 36002
       B = 0.000000e+00
       E = 3.600100e+03
  IFTYPE = TIME SERIES FILE
   LEVEN = TRUE
   DELTA = 1.000000e-01
  DEPMIN = -5.193068e+00
  DEPMAX = 5.205983e+00
  DEPMEN = 1.918942e-06
 OMARKER = 0
  KZDATE = APR 15 (105), 2017
  KZTIME = 06:30:00.000
   KSTNM = S0001
    STLA = 1.000004e-01
    STLO = 1.050000e+02
    STEL = 0.000000e+00
    STDP = 0.000000e+00
    EVLA = 1.000004e-01
    EVLO = 1.000000e+02
    EVDP = 2.000000e+04
   KHOLE = SE
    DIST = 5.565966e+02
      AZ = 8.999564e+01
     BAZ = 2.700044e+02
   GCARC = 4.999992e+00
  LOVROK = TRUE
   USER0 = 1.000000e+00
  KUSER0 = Syngine
  KUSER1 = prem
  KUSER2 = i_2s
   NVHDR = 6
  LPSPOL = TRUE
  LCALDA = FALSE
  KCMPNM = BXZ
  KNETWK = XX
     MAG = 8.686665e+00
 IMAGTYP = Moment Magnitude