DPAM: Programs for Aeromagnetic Survey Data Processing

Contents
alog2asc     despike     ggrid pchkdv xslin / xslina Various line data Format
xldam dvcorr ggrids pchkmag alog2asc output Format       StdLIN data Format
xldpn ecomp pframe     pchkres GSmag data Format   DPAM line data Format
xldhg fcomp pltrk pchkcomp     line information Format       HGAM data Format
 
Program Name Function
alog2asc Convert AIRLOGS airborne binary raw data into ASCII file Format.
          Parameters: log filename
input binary data filename
output ASCII data filename
xldam Generate DPAM line data file from airborne ASCII raw data by 'alog2asc' making use of Real-time GPS position data included, with calculation of IGRF residuals.
          Parameters: log filename
filename of survey line information data
output DPAM line data filename
survey year
IGRF generation number
thin-out ratio N (crop 1 out of N data)
Filename of input airborne ASCII raw data is specified in the survey line information data.
xldpn Generate DPAM line data file from airborne ASCII raw data by 'alog2asc' and PostNav GPS position data, with calculation of IGRF residuals.
          Parameters: log filename
filename of survey line information data
output DPAM line data filename
survey year
IGRF generation number
thin-out ratio N (crop 1 out of N data)
Filenames of input airborne ASCII raw data and PostNav GPS position data are specified in the survey line information data.
xldhg Generate HGAM line data file (similar to DPAM line data) from helicopter-borne gradiometer AM (HGAM) data, making use of HGAM bird-mag data and Real-time or PostNav GPS position data, with diurnal correction by GSmag data and calculation of IGRF residuals.
          Parameters: log filename
filename of survey line information data
Pos. data spec.: 0(Real-time) or 1(PNAV-DGPS)
input GSmag data filename
output DPAM line data filename
survey year
IGRF generation number
magnetic sensors vertical separation (m)
thin-out ratio N (crop 1 out of N data)
Filenames of input HGAM bird-mag data and Real-time/PostNav GPS position data are specified in the survey line information data.
despike Eliminate magnetic field spike noise in DPAM line data.
          Parameters: log filename
input DPAM line data filename
output DPAM line data filename
dvcorr Correct for magnetic field diurnal variation in DPAM line data, making use of GSmag data.
          Parameters: log filename
input DPAM line data filename
input GSmag data filename
output DPAM line data filename
ecomp Execute compensation of aircraft magnetic effect for DPAM CompBox line data, using line data of CompBox flight itself. (Test purpose)
          Parameters: log filename
filename of DPAM CompBox data
output DPAM line data filename
fcomp Execute compensation of aircraft magnetic effect for DPAM survey line data, using DPAM line data of CompBox flight.
          Parameters: log filename
filename of DPAM CompBox data
filename of input DPAM survey line data
filename of output DPAM survey line data
ggrid Generate magnetic field grid data from DPAM line data or equivalent, by the method developed by Smith and Wessel [1990].
          Parameters: log filename
input AM line data file-type (*1)
input AM line data filename
Geodetic system of input data [WGS(1) or TYO(2)]
[if random file] data formatting parameter (*2)
effecting radius (km)
areaname label
map projection coordinate number
grid location parameters (*3)
output grid filename
ggrids Generate grid data of magnetic field and observation altitude from DPAM line data or equivalent, by the method developed by Smith and Wessel [1990].
          Parameters: log filename
input AM line data file-type (*1)
input AM line data filename
Geodetic system of input data [WGS(1) or TYO(2)]
[if WGS(1)] Altitude Reference [GRS(1) or Geoid(2)]
[if random file] data formatting parameter (*2)
effecting radius (km)
areaname label
map projection coordinate number (NC)
[if NC>=200] Altitude Reference of output [GRS(1) or Geoid(2)]
grid location parameters (*3)
output grid filename
pframe Draw map of coordinates framework of survey area. (For easier setting of grid location parameters.)
          Parameters: log filename
output PS filename
areaname
map projection coordinate number
Latitude/Longitude range
drawing parameter
pltrk Draw trackline paths from DPAM line data.
          Parameters: log filename
input AM line data file-type (*1)
input AM line data filename
Geodetic system of input data [WGS(1) or TYO(2)]
[if random file] data formatting parameter (*2)
output PS filename
areaname
map projection coordinate number
location parameters
drawing parameters
pchkdv Plot GSmag data.
          Parameters: log filename
input GSmag data filename
output PS filename
pchkmag Plot magnetic total field data of DPAM line data (in black).
          Parameters: log filename
input DPAM line data filename
output PS filename
pchkres Plot IGRF residual magnetic field data of DPAM line data (in blue).
          Parameters: log filename
input DPAM line data filename
output PS filename
pchkcomp Plot IGRF residual magnetic field data before and after the compensation of aircraft magnetic effect, for the output DPAM file from the process ecomp/fcomp.
          Parameters: log filename
input DPAM line data filename
output PS filename
xslin Convert various format line data into StdLIN standard line data.
          Parameters: log filename
input AM line data file-type (*1)
input AM line data filename
Geodetic system of input data [WGS(1) or TYO(2)]
[if WGS(1)] Altitude Reference [GRS(1) or Geoid(2)]
[if generic random file] data formatting parameter (*2)
output StdLIN data filename
Geodetic system of output data [WGS(1) or TYO(2)]
[if WGS(1)] Altitude Reference [GRS(1) or Geoid(2)]
xslina Extract StdLIN line data with averaged re-sampling from DPAM line data.
          Parameters: log filename
input DPAM line data filename
Geodetic system of input data [WGS(1) or TYO(2)]
[if WGS(1)] Altitude Reference [GRS(1) or Geoid(2)]
time interval of averaged re-sampling (sec.)
output StdLIN data filename
Geodetic system of output data [WGS(1) or TYO(2)]
[if WGS(1)] Altitude Reference [GRS(1) or Geoid(2)]
(*1) There are variations of file types of AM line data as follows: 1: DPAM survey line data, 2: AMDB-GSJ located line data, 3: AMDB-NEDO integrated located data, 4: StdLIN standard line data, 0: generic random point data.
The detail of generic random point data file is specified by the data formatting parameter (*2).
(*2) Data formatting parameter includes the unit [minute(1) or degree(2)] of latitudes/longitudes, and the sequence numbers for latitude, longitude, altitude (in m) and magnetic field (in nT) data in the free-format data string.
(*3) "grid location parameters" include Northing and Easting of Southwest corner, mesh interval and number of mesh to the North, and to the East.

ASCII airborne raw data output from "alog2asc" (example)

 
//alog2asc v.2003-11-26 by T. Nakatsuka
//InputDataFilename: 030215_132849.B00
/AlogVersion 2.0200
/DateTime: 20030215 13:28:50.07  (JulianDay:  46)
/Date: 2003 - 02 - 15
/Time: 13 : 28 : 50+0.060
/SensorType: 0(Cesium)
/Flight#:  0
/CyclingInterval:  0.050 sec
/Analog0: slope=    1.000, offset=    0.000
/Analog1: slope=    1.000, offset=    0.000
/Analog2: slope=    1.000, offset=    0.000
/Analog3: slope=    1.000, offset=    0.000
/Analog4: slope=    1.000, offset=    0.000
/Analog5: slope=    1.000, offset=    0.000
/Analog6: slope=    1.000, offset=    0.000
/Analog7: slope=    1.000, offset=    0.000
/   FID     SYSTIME      t200       MAG     FGx     FGy     FGz    Ralt    Balt     AD6     AD7     AD8      UTC       LAT        LON     ALT  Q  N
  911.7 13:28:50.07   757.842 46654.164  -3.838   2.534  -0.757  -1.255  -0.010  -0.654   0.000   0.000  4.51931  35.25182  136.92375   16.85  1  7
  911.8 13:28:50.13   757.877 46654.270  -3.838   2.532  -0.771  -1.230  -0.010  -0.635   0.000   0.000   *         *          *          *    *  *
  911.9 13:28:50.24   758.003 46654.295  -3.833   2.534  -0.781  -1.216  -0.010  -0.635   0.000   0.000   *         *          *          *    *  *
  912.0 13:28:50.29   758.027 46654.358  -3.833   2.532  -0.752  -1.245  -0.005  -0.625   0.000   0.000  4.51944  35.25182  136.92375   16.86  1  7
  912.1 13:28:50.40   758.164 46654.469  -3.843   2.534  -0.771  -1.216  -0.005  -0.635   0.000   0.000   *         *          *          *    *  *
     .......

Ground station magnetic field data (example)

 
/Base:  46490           <-- Baseline value (nighttime value of quiet day) (*)
/Date: 20030215         <-- Date (8 columns of "yyyymmdd") (*)
130008 464795
130023 464802
130038 464795
130053 464803           <-- Acquired data from ground station magnetometer
130108 464805           <-- 6 cols Time "HHMMSS", 1 col space,
130123 464807           <--  and 6 cols magnetic field (in 0.1nT unit)
130138 464806
130153 464805
   .......
        (*) If Baseline value and/or Date is specified in the midst of file,
            it is effective rearward.

PostNav DGPS / Real-time GPS position data (example)

 
   03:51:11.000 35.096095 137.635373 983.83
   03:51:12.000 35.096319 137.635368 985.57
   03:51:13.000 35.096544 137.635363 987.19
        .......
  05:14:46.00  36.440488  138.535838  1408.51
  05:14:47.00  36.440488  138.535838  1408.50
  05:14:48.00  36.440488  138.535838  1408.47
        .......
     All lines are GPS position data in free format consisting of UTC time,
       latitude (in degrees), longitude (in degrees) and altitude (in m).
       Time data must be in the form of "HH:MM:SS.tt".

Survey line information data (example)

 
=030217f1.asc  030217f1.pnav
220      095250 100100
210      100330 101000
200      101210 101950
     .......
140      111210 112050
130      112340 113120
=030217f2.asc  030217f2.pnav
120      121300 122010
110      122235 122840
100      123105 123850
     .......
        Lines starting with '=' on the 1st column specify data file,
          giving filenames of ASCII raw data and GPS position data.
          (Prog. xldam does not require filename of GPS position data.)
        All other lines are individual survey line information, i.e.,
          Line name, Start time and End time separated by space.
          (The time format is "hhmmss.tt", where ".tt" can be omitted.)

Various Line data File Format

 
  There is variations of AM line data file formats, as follows.
    1) DPAM line data file
    2) AMDB-GSJ located line data file
    3) AMDB-NEDO integrated located data file
    4) StdLIN standard line data file
    0) Generic random point data file
  In the file format of 2 and 3, latitude and longitude values are referred to 
WGS (World Geodetic System), and altitude values are elevation from the Geoid. 
However, there is no such rule in other types of format, and the user has to 
specify the sort of geodetic system, etc.
  The format type 0 is one for manipulating general versatile data, and the 
unit of latitude and longitude values and the sequence of each data are to be 
specified.
  Commonly, individual point data consists 1 line data, the 1st column of 
which is a blank or the 1st digit of a value.  To indicate the start of new 
line with any attribute information, there is a header line starting with 
"&", "#" or "%" at the 1st column.  Also, there may exist some comment 
lines starting with "#".
(Accordingly, the omission of lines starting with "&", "%" and "#" gives 
the series of valid point data.)

StdLIN line data format (example)

 
# Areaname: Kobe-Kyoto
# Survey Date: 1995.12.07-12.27
&A-01
 2079.0222N  8116.2764E   277.8m   -45.1nT
 2079.0405N  8116.3164E   278.5m   -44.6nT
 2079.0588N  8116.3564E   279.1m   -44.4nT
        .......
 2087.3958N  8134.2559E   275.4m   -48.3nT
 2087.4158N  8134.2964E   275.4m   -53.6nT
&    C-2r
 2088.2712N  8134.3799E   279.1m   -44.9nT
 2088.2563N  8134.3384E   279.3m   -40.8nT
 2088.2407N  8134.2964E   279.6m   -40.1nT
        .......
     Lines starting with '#' are comment information, usually placed only at
       the head of the file.  (Never be placed among series of line data.)
     Lines starting with '&' or '%' indicate the start of line data.
       Line name (number) is described in 2nd-9th columns, and the form of
       the rest is not restricted.  (Starting time and number of data points
       included are commonly described.)
       In some cases, a line with no data points is defined for explicit
       declaration of the end of file.
     All other lines are data of individual points, consisting of Latitude
       (in minutes), Longitude (in minutes), Altitude (in m), and Residual
       magnetic anomaly (in nT) data, with the format (42 columns) of
          format(f10.4, 1hN, f11.4, 1hE, f8.1, 1hm, f8.1, 2hnT).

DPAM line data format (example)

 
# Areaname: Ootoge
# Survey Date: 2003.02.17
&220        95250.00 100100.00
 4188.6 20030217  95250.02  3  35.08857  137.71223 1033.2 46445.27   -50.13  -3.535   2.783   1.099   3170.02
 4188.7 20030217  95250.09  3  35.08859  137.71223 1033.3 46445.02   -50.39  -3.525   2.783   1.108   3170.09
 4188.8 20030217  95250.17  3  35.08860  137.71223 1033.3 46445.90   -49.51  -3.545   2.781   1.084   3170.17
        .......
 4946.6 20030217 100059.89  3  35.20598  137.71225 1258.3 46440.41  -115.48  -3.560   2.891   0.713   3659.89
 4946.7 20030217 100059.95  3  35.20598  137.71225 1258.3 46439.93  -115.95  -3.555   2.874   0.708   3659.95
&210       100330.00 101000.00
 5177.8 20030217 100330.09  3  35.20476  137.70676 1247.5 46418.68  -138.34  -3.281  -3.225  -0.249   3810.09
 5177.9 20030217 100330.19  3  35.20473  137.70676 1247.4 46418.48  -138.52  -3.296  -3.230  -0.273   3810.19
 5178.0 20030217 100330.29  3  35.20470  137.70677 1247.3 46418.52  -138.47  -3.286  -3.210  -0.288   3810.29
        .......
     Lines starting with '#' are comment information, usually placed only at
       the head of the file.  (Never be placed among series of line data.)
     Lines starting with '&' or '%' indicate the start of line data,
       describing Line name (number) and Start/End time.
       Time data is double precision value in the form of "HHMMSS.tt".
     All other lines are data of individual points (109 columns + LF).
           format(f7.1, 1x,i8, 1x,f9.2, 1x,i2, 1x,f9.5, 1x,f10.5, 1x,f6.1,
          *       2(1x,f8.2), 3(1x,f7.3), 1x,f9.2)
             1) Fiducial number, 2) Date (yyyymmdd), 3) Time (HHMMSS.tt), 
             4) Data spec.(*), 5) Latitude (Deg.), 6) Longitude (Deg.),
             7) Altitude (m), 8) Magnetic field (nT), 9) IGRF residual (nT),
             10-12) Fluxgate 3 components values (V), 
             13) UTC seconds (from JST 09:00, minus before 9AM)
       In case of output from ecomp/fcomp, following data related to the
       aircraft magnetic field compensation are added with format (4(1x,f8.2)).
             14) residual before compensation (tres),
             15) correction for aircraft magnetic field (corr), 
             16) random variation component (rand),
             17) linear trend component (trend),
             [tres = corr + rand + trend]
       (*) meaning of Data spec.(k) :
          k = 4,5,6,7 :   5) Lat., 6) Long., 7) Alt. are from Real-time GPS
          k = 0,1,2,3 :   5) Lat., 6) Long., 7) Alt. are from PostNav DGPS
          k = 2,3,6,7 :   8) Mag.F, 9) IGRFres. are not diurnal corrected yet
          k = 0,1,4,5 :   8) Mag.F, 9) IGRFres. are diurnal corrected already
          k = 1,3,5,7 :   8) Mag.F, 9) IGRFres. are not AMF compensated yet
          k = 0,2,4,6 :   8) Mag.F, 9) IGRFres. are AMF compensated already

Bird-mag data and Line data in Helicopter-borne gradiometer AM (HGAM)

   [ HGAM bird-mag data format ] (example) 
        .......
 20051012 09:14:51.10  99999.99  46949.90
 20051012 09:14:51.20  99999.99  46949.89
 20051012 09:14:51.30  99999.99  46949.85
 20051012 09:14:51.40  46781.33  46949.85
 20051012 09:14:51.50  99999.99  46949.79
 20051012 09:14:51.60  99999.99  46949.77
 20051012 09:14:51.70  46795.16  46949.70
 20051012 09:14:51.80  46850.40  46949.78
 20051012 09:14:51.90  46851.73  46949.73
 20051012 09:14:52.00  46851.76  46949.70
        .......
     Each data consists of  Date (yyyymmdd), Time (HH:MM:SS.tt),
       Total force magnetic field at 1st sensor (nT), and
       Total force magnetic field at 2nd sensor (nT),
       with the form (41 columns + LF) as follows.
          format(1x, i8, 1x, i2,1h:,i2,1h:,f5.2, 1x, f9.1, 1x, f9.1)
  [ HGAM line data format ] (example) 
&F13       142618.00 152530.00
 189303 20051012 142618.00 82  36.43241  138.42609 2285.5 46934.03   -58.27 46936.09   -56.09    -2.06
 189304 20051012 142618.10 82  36.43238  138.42610 2285.4 46934.69   -57.58 46936.12   -56.03    -1.43
 189305 20051012 142618.20 82  36.43235  138.42612 2285.4 46935.28   -56.97 46936.75   -55.38    -1.47
        .......
 224821 20051012 152529.80 82  36.42001  138.58405 2700.9 47043.23   112.45 47048.76   118.09    -5.53
 224822 20051012 152529.90 82  36.42004  138.58408 2700.4 47043.27   112.47 47048.77   118.09    -5.50
 224823 20051012 152530.00 82  36.42006  138.58409 2699.9 47042.84   112.02 47048.52   117.81    -5.67
&F23a      125215.00 130130.00
 138808 20051013 125215.00 82  36.40794  138.52861 2771.7 47531.58   593.48 47536.52   598.54    -4.94
 138809 20051013 125215.10 82  36.40793  138.52858 2772.0 47531.73   593.64 47536.70   598.73    -4.98
 138810 20051013 125215.20 82  36.40791  138.52856 2772.3 47531.83   593.75 47536.73   598.77    -4.90
 138811 20051013 125215.30 82  36.40790  138.52853 2772.6 47531.95   593.87 47536.86   598.90    -4.91
        .......
     Lines starting with '&' indicate the start of line data,
       describing Line name (number) and Start/End time.
       Time data is double precision value in the form of "HHMMSS.tt".
     All other lines are data of individual points (102 columns + LF).
           format(i7, 1x,i8, 1x,f9.2, 1x,i2, 1x,f9.5, 1x,f10.5, 1x,f6.1,
          *       5(1x,f8.2))
             1) Fiducial number, 2) Date (yyyymmdd), 3) Time (HHMMSS.tt), 
             4) Data spec.(*), 5) Latitude (Deg.), 6) Longitude (Deg.),
             7) Altitude (m), 8) MagneticField-1(nT), 9) IGRFresidual-1 (nT),
             10) MagneticField-2 (nT), 11) IGRFresidual-2 (nT),
             12) Magnetic field difference (nT), 
       (*) Data spec.(k) :
          k = 82  if position data is recovered by PostNav DGPS
          k = 86  if position data is recovered by Real-time GPS
          (not diurnal corrected yet, no need of AMF compensation)
     This data has the form of a variation of DPAM line data.
       It can be processed much the same as DPAM line, as far as dealing
       with MagneticField-1 value.
       When dealing with MagneticField-2 value, the file shall be processed
       as a generic random point data file.

AMDB-GSJ line data format

   Located line data file from GSJ digital data processing consists of 1 row of areaname
header and a repetition of line data blocks, and the line data block is composed of 1 row
line header and repeated point data. The format of each data row is as follows.
nameoffsetcolsformat Contents
(Areaname Header) 
-02 A2fixed string   ‘##’
-22 2X (space)
area48 A8Area name
year128 F8.2Year of survey (as used for DGRF calculation)
high206 F6.0Altitude in ft
-262 A2fixed string   ‘ft’
(Line Header) 
-02 A2fixed string   ‘# ’
lnam28 A8Line name (aligned left)
npt106 I6Number of point data included
(Point data)   (repeat npt times)
isec08 I8Time in seconds (converted from DDHHMMSS string)
alat89 F9.3Latitude in minutes (ITRF)
alon179 F9.3Longitude in minutes (ITRF)
tres268 F8.1DGRF residual magnetic value in nT after all corrections


AMDB-NEDO line data format

   Integrated located data file of NEDO survey consists of 1 row of areaname header and
a repetition of line data blocks, and the line data block is composed of 1 row line header
and repeated point data. The format of each data row is as follows.
nameoffsetcolsformat Contents
(Areaname Header) 
-02 A2fixed string   ‘##’
-28 A8fixed string   ‘  NEDO   ’
area108 A8Area name
(kyushu / tohoku / hokkaido / chubu / kanto / chugoku)
(Line Header) 
-02 A2fixed string   ‘# ’
lnam28 A8Line name (aligned right)
npt106 I6Number of point data included
(Point data)   (repeat npt times)
ifid08 I8Fiducial number
isec86 I6Time of a day in seconds
alat149 F9.3Latitude in minutes (ITRF)
alon239 F9.3Longitude in minutes (ITRF)
tair328 F8.1Magnetic field in the air in nT
tmdv408 F8.1Magnetic diurnal variation in nT
tcor488 F8.1Magnetic field in nT after diurnal correction
and level adjustment
tres568 F8.1DGRF residual in nT after correction and adjustment
irad645 I5Radio altimeter value in ft
ibar695 I5Barometric altimeter value in ft