The unified data format¶

All projects in our working group use a unified format such that data are transpararent and transportable. There are a lot of import and export filters for third party software or hardware, but internally the following structure is used. Since the most applications use multi-electrode systems they are based on the way they are addressed (and computed in modeling).

Every data set consists of two mandatory parts: electrode definitions and arrangement definition. Subsequently the number of electrodes, their positions (x z for 2D, x y z for 3D), the number of data and their definitions are given. Comments may be places after the # character.

After the number of data the definition for each datum is given row-wise by the electrode numbers for the current electrodes A and B (C1 and C2) and the potential electrodes M and N (P1 and P2). Please not all electrode number starting from one. Electrodes with a zero number will be treated as infinity electrodes. They may be followed by other attributes (see list below). Standard is the apparent resistivity and optional the relative error as exemplified for a tiny dipole-dipole survey.

6# Number of electrodes
# x z position for each electrode
0     0
1     0
2     0 # loose ground
3     0
4     0
5     0
6# Number of data
# a b m n rhoa
1   2   3   4  231.2
2   3   4   5  256.7
3   4   5   6  312.8
1   2   4   5  12.1 # possibly an outlier
2   3   5   6  199.7
1   2   5   6  246.2


If other fields or order are used, a token string in the line after the data number specifies the given fields. The token may be followed by a slash and a physical unit. The following tokens are allowed (case insensitive). Tokens Meaning possible units

• a c1 electrode number for A (C1)
• b c2 electrode number for B (C2)
• m p1 electrode number for M (P1)
• n p2 electrode number for N (P2)
• rhoa Ra apparent resistivity Ohmmeter
• rho r Resistance Ohm
• err relative measurement error in %/100 (default)
• ip IP measure mRad(default)
• ipErr absolute IP measure error in mRad(default)
• i I Current A(default),mA,uA
• u U Voltage V(default),mV,uV

The following sample contains voltages, currents and a percentage error.

...
6# Number of data
# a b m n u i/mA err/%
1   2   3   4  -0.5305165 102.2 2.4
2   3   4   5  -0.5305165 99.9  1.4
3   4   5   6  -0.5305165 95.6  2.6
1   2   4   5  -0.1326291 100.1 7.6
2   3   5   6  -0.1326291 80.2 8.6
1   2   5   6  -0.05305165 77.3 7.5


Topography may be given in two ways.

1. Each electrode can be given a height value as z position (preferred by webinv).
2. Alternatively, the data may be followed by a topo list (preferred by DC2dInvRes).
...
1   2   5   6  -0.05305165  7.5
4# Number of topo points
# x h for each topo point
0 353.2
12 357.1
19 359.9
24.5 350


will follow¶

Buried/borehole electrodes

Spectral IP data

will follow