There
is
one Geosoft XYZ file corresponding to each survey method (magnetic,
radiometric and electromagnetic measurements) and each QDS map sheet.
In addition to the measured component files there are also separate
files for calculated apparent resistivities, digital terrain models and
total gamma-ray dose data.
As
the map sheets 4-5, 12-13 and 153-155 were surveyed using one
magnetometer whereas on the map sheets 30-31, 44-45, 62 and 78, two
magnetometers were used, there are two different naming conventions and
file structures for magnetic data files.
The files are
named as follows (# means the varying QDS map sheet number):
AP#.XYZ
apparent resistivity data (all map sheets)
DTM#.XYZ digital terrain model (all map
sheets)
EM#.XYZ
electromagnetic data (all map sheets)
MB#.XYZ back boom
magnetometer data (map sheets 4-5, 12-13, 153-155)
ML#.XYZ left
wingtip magnetometer data (map sheets 30-31, 44-45, 62, 78)
MR#.XYZ right wingtip
magnetometer data (map sheets 30-31, 44-45, 62, 78)
RA#.XYZ
radiometric data (all map sheets)
TO#.XYZ
gamma-ray dose data (all map sheets)
Each row in
these ASCII files corresponds to one measurement point. One column of
the row corresponds to one measurement parameter.
Electromagnetic
data
files
X,
Y ARC1960 coordinate pair X, Y
(easting, northing respectively) (meters)
DAY Day number from the beginning of the
year
TIME Measurement time stamp (hhmmss)
DIR Flight direction
(degrees, clockwise from north)
RALT Radar altitude (meters)
LFR In-phase component of the
lower frequency (3 005 / 3 125 Hz) (ppm)
LFI Quadrature
component of the lower frequency (3 005 / 3 125 Hz) (ppm)
HFR In-phase component of the
higher frequency (14 368 Hz) (ppm)
HFI Quadrature component of
the higher frequency (14 368 Hz) (ppm)
Magnetic data
files: map sheets 4-5, 12-13, 153-155
X,
Y ARC1960 coordinate pair X, Y
(easting, northing respectively) (meters)
DAY Day number from the beginning of the
year
TIME Measurement time stamp (hhmmss)
DIR Flight direction
(degrees, clockwise from north)
RALT Radar altitude (meters)
MB65 Total magnetic field of the back boom
magnetometer at IGRF65 level (nT)
Magnetic data
files: map sheets 30-31, 44-45, 62, 78
X,
Y ARC1960 coordinate pair X, Y
(easting, northing respectively) (meters)
DAY Day number from the beginning of the
year
TIME Measurement time stamp (hhmmss)
DIR Flight direction
(degrees, clockwise from north)
RALT Radar altitude (meters)
ML65 Total magnetic field of the left wingtip
magnetometer at IGRF65 level (nT)
MR65 Total magnetic field of the right wingtip
magnetometer at IGRF65 level (nT)
Radiometric
data files
X,
Y ARC1960 coordinate pair X, Y
(easting, northing respectively) (meters)
DAY Day number from the beginning of the
year
TIME Measurement time stamp (hhmmss)
DIR Flight direction
(degrees, clockwise from north)
RALT Radar altitude (meters)
BALT Barometric altitude (m)
TOUT Temperature outside the aircraft (°C)
D_KAL Potassium concentration (% K)
D_URA Uranium concentration (ppm equivalent uranium eU)
D_THO Thorium concentration (ppm equivalent thorium eTh)
Apparent
resistivity data files
X,
Y ARC1960 coordinate pair X, Y
(easting, northing respectively) (meters)
DAY Day number from the beginning of the
year
TIME Measurement time stamp (hhmmss)
DIR Flight direction
(degrees, clockwise from north)
RALT Radar altitude (meters)
LFA Calculated lower frequency (3
005 / 3 125 Hz) apparent resistivity (m)
LFS Calculated apparent depth
corresponding to LFA (m)
HFA Calculated higher frequency (14
368 Hz) apparent resistivity (m)
HFS Calculated apparent depth
corresponding to HFA (m)
Digital
terrain model files
X,
Y ARC1960 coordinate pair X, Y
(easting, northing respectively) (meters)
DAY Day number from the beginning of the
year
TIME Measurement time stamp (hhmmss)
DIR Flight direction
(degrees, clockwise from north)
RALT Radar altitude (meters)
DTM Digital terrain model above the WGS84
ellipsoid (m)
Gamma-ray
dose data
X,
Y ARC1960 coordinate pair X, Y
(easting, northing respectively) (meters)
DAY Day number from the beginning of the
year
TIME Measurement time stamp (hhmmss)
DIR Flight direction
(degrees, clockwise from north)
RALT Radar altitude (meters)
BALT Barometric altitude (m)
08:38:50TOUT Temperature outside the aircraft (°C)
D_TOT Dose rate (nGy/h
Grids
The grids are
interpolated with the minimum curvature algorithm of Geosoft Oasis
Montaj for all the parameters except apparent resistivity in which
Akima spline method is used. Grid cell size is 50 meters for all the
grids.
There is a
corresponding grid for all the geophysical parameters of each map
sheet. In addition there are also grids for digital terrain models
(base level WGS84 ellipsoid). The units of the grid values correspond
to those in the XYZ files.
Grids are named as follows (# means the varying QDS
map sheet number):
DTM#.GRD Digital terrain model
HFA#.GRD Higher frequency (14
368 Hz) apparent resistivity
HFI#.GRD Higher
frequency (14 368 Hz) EM quadrature component
HFR#.GRD Higher frequency (14
368 Hz) EM in-phase component
KAL#.GRD Potassium
LFA#.GRD Lower frequency (3
005 / 3 125 Hz) apparent resistivity
LFI#.GRD Lower
frequency (3 005 / 3 125 Hz) EM quadrature component
LFR#.GRD Lower
frequency (3 005 / 3 125 Hz) EM in-phase component
MAG#.GRD Magnetic total field
THO#.GRD Thorium
TOT#.GRD Total radiation dose
rate
URA#.GRD Uranium
Contacts: info@gst.go.tz
