4.1.4. EM Data

• 4.1.4.1. EM Data Type Functionality
  • 4.1.4.1.1. Defining Transmitters
  • 4.1.4.1.2. Defining Receivers
  • 4.1.4.1.3. Remove Transmitters
  • 4.1.4.1.4. Remove Receivers
  • 4.1.4.1.5. Waveform (TDEM objects only)
• 4.1.4.2. EM Data Manipulation
  • 4.1.4.2.1. Extract data based on times or frequencies
  • 4.1.4.2.2. View and/or edit the times or frequencies of a data set
  • 4.1.4.2.3. Compute Biot-Savart Primary Field (3D object only)
  • 4.1.4.2.4. Set Data Normalization (FEM and TEMsounding Only)
  • 4.1.4.2.5. Set Time Normalization (TEM1Dsounding Only)
  • 4.1.4.2.6. Calculate Transmitter-Receiver seperation
  • 4.1.4.2.7. Parse FEM/TEM 3D Sounding by Transmitter
  • 4.1.4.2.8. Merge Parsed FEM/TEM 3D Soundings

There are 6 main types of EM data that can be created in GIFtools.

• FEM1Dsounding and TEM1Dsounding

• FEMdata

• TEMdata

• FEM3Dsounding

• TEM3Dsounding

4.1.4.3. FEMdata

For the FEMdata class, we assume the receivers measure the E and/or H-field along the Cartesian directions. Transmitters associated with this data class can be:

• magnetic dipoles

• large-loop inductive sources

• galvanic sources

The FEMdata is used in conjunction with the following codes:

• E3Dv1

4.1.4.4. TEMdata

For the TEMdata class, we assume the receivers measure E, H or dB/dt along the Cartesian directions. Transmitters associated with this data class can be:

• magnetic dipoles

• large-loop inductive sources

• galvanic sources

The TEMdata is used in conjunction with the following codes:

• H3DTD

• TDoctree v1

4.1.4.4.1. FEM1Dsounding and TEM1Dsounding

For the FEM1Dsounding and TEM1Dsounding classes, parameters describing both the transmitter and receiver are required and used in the forward and inverse problems. This is the most general format. It allows to easily store airborne data collected from transmitters and receivers of arbitrary shapes and orientations.

For FEM1Dsounding and FEM1Dsounding objects, transmitters can either be defined as a dipole or loop source. The position of the receiver is set relative to the transmitter locations. The following parameters are required:

• Along-line offset: The along-line position of receivers, relative to transmitter locations

• Cross-line offset: The cross-line position of receivers, relative to transmitter locations

• Vertical offset: The vertical location of the receivers relative to the surface

• Dipole Moment: Uses a right-handed positive down coordinate system

The FEM1Dsouding data class isused for:

• EM1DFM inversion,

And the FEM1Dsounding data class is used for:

• EM1DTM inversion

4.1.4.4.2. FEM3Dsounding

For FEM3Dsounding objects, the receivers measure either the E or H-field along the direction specified by the receiver. Although each datum is associated with a location, the user must define the transmitters and receivers explicitly. For this data object:

• inductive sources and H-field receivers are defined using closed loops

• galvanic sources and E-field receivers are defined when we do not close the loop

This data class is use for:

• E3Dv2

• E3Dv2 tiled

4.1.4.4.3. TEM3Dsounding

For TEM3Dsounding objects, the receivers measure either E, H or dB/dt along the direction specified by the receiver. Although each datum is associated with a location, the user must define the transmitters and receivers explicitly. For this data object:

• inductive sources, H-field receivers and dB/dt receivers are defined using closed loops

• galvanic sources and E-field receivers are defined when we do not close the loop

This data class is use for:

• TDoctree v2

• TDRH v2