.. DO NOT EDIT. .. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY. .. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE: .. "gallery/fdomain/ipandq.py" .. LINE NUMBERS ARE GIVEN BELOW. .. only:: html .. note:: :class: sphx-glr-download-link-note :ref:`Go to the end ` to download the full example code. .. rst-class:: sphx-glr-example-title .. _sphx_glr_gallery_fdomain_ipandq.py: In-phase and Quadrature ======================= Profiling measurements using small sources are often analysed in terms of in-phase and quadrature readings, see, e.g., Frischknecht et al., 1991. In this method, the in-phase and quadrature components are the real and imaginary part, respectively, of the ratio of the secondary field (total field without direct wave) over the primary field (direct wave, usually the airwave). This ratio is often multiplied by a factor, and then given as, for instance, ppt (factor 1e3) or ppm (factor 1e6). This example demonstrates the use of :func:`empymod.model.ip_and_q`, the wrapper to obtain in-phase and quadrature components for a given model and a given system, with the GEM-2 and the DUALEM-842 equipments. **Reference** - **Frischknecht, F.C., V.F. Labson, B.R. Spies, and W.L. Anderson, 1991**, Profiling Methods Using Small Sources: Chapter 3 in *Electromagnetic Methods in Applied Geophysics: Volume 2, Application, Parts A and B*, 105-270; DOI: `10.1190/1.9781560802686.ch3 `_. With the help and expertise of María Carrizo Mascarell (`@mariacarrizo `_). .. GENERATED FROM PYTHON SOURCE LINES 30-36 .. code-block:: Python import empymod import numpy as np import matplotlib.pyplot as plt plt.style.use('ggplot') .. GENERATED FROM PYTHON SOURCE LINES 37-43 GEM-2 ----- The GEM-2 is a fixed beam system with a transmitter coil and a receiver coil, manufactured by `Geophex Ltd. `_. It can operate up to 10 frequencies btw. 30 Hz and 93 kHz. .. GENERATED FROM PYTHON SOURCE LINES 43-78 .. code-block:: Python # Define your configuration height = 1.0 # Your equipment height above ground ab = 66 # Your configuration: 66 for HCP or 55 for VCP # Your chosen frequencies freq = np.logspace(np.log10(30), np.log10(93000), 10) # Collect system details GEM2 = { 'src': [0, 0, -height], 'rec': [1.66, 0, -height], # GEM-2 has a coil separation of 1.66 m 'freqtime': freq, 'ab': ab, 'verb': 1, } # Define your model model1 = { 'depth': [0, 2, 5], # Half-space, 2m, 3m, half-space 'res': [2e14, 50, 0.1, 50], # Conductive middle layer 'mpermH': [1, 1, 1.5, 1], # Middle layer with a magn. susc. of 0.5 # Optionally additional parameters: aniso, epermH, epermV, mpermV } IP1, Q1 = empymod.ip_and_q(**model1, **GEM2) fig1, ax1 = plt.subplots(1, 1) ax1.semilogx(freq, IP1, '-o', label='In-phase') ax1.semilogx(freq, Q1, '-o', label='Quadrature') ax1.set_title('GEM-2') ax1.set_xlabel('Frequency (Hz)') ax1.set_ylabel('IP or Q (ppt)') ax1.legend() .. image-sg:: /gallery/fdomain/images/sphx_glr_ipandq_001.png :alt: GEM-2 :srcset: /gallery/fdomain/images/sphx_glr_ipandq_001.png :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 79-86 DUALEM-842 ---------- The DUALEM-842 is a fixed beam system with a transmitter coil and six receiver coil: one coplanar at 2, 4, and 8 m offset, and one perpendicular at 21., 4.1, and 8.1 m offset. Operation frequency is 9 kHz. It is manufactured by `Dualem Inc. `_. .. GENERATED FROM PYTHON SOURCE LINES 86-143 .. code-block:: Python height = 1.0 # Equipment height def dualem(height, model, ab, scale=1e3): """We wrap the system to accommodate the different configurations.""" # The system DUALEM842S = { 'src': [0, 0, -height], 'freqtime': 9000, 'verb': 1, } # Pre-allocate output IP = np.zeros((len(ab), 3)) Q = np.zeros((len(ab), 3)) # Loop over configurations for i, a in enumerate(ab): if a == 46: offset = [2.1, 4.1, 8.1] else: offset = [2.0, 4.0, 8.0] DUALEM842S['rec'] = [offset, [0, 0, 0], -height] DUALEM842S['ab'] = a IP[i, :], Q[i, :] = empymod.ip_and_q( **model, **DUALEM842S, scale=scale ) return IP, Q # Define your model model2 = { 'depth': [0, 2, 5], # Half-space, 2m, 3m, half-space 'res': [2e14, 50, 0.1, 50], # Conductive middle layer 'mpermH': [1, 1, 1.5, 1], # Middle layer with a magn. susc. of 0.5 # Optionally additional parameters: aniso, epermH, epermV, mpermV } ab = [66, 55, 46] IP2, Q2 = dualem(height, model=model2, ab=ab) fig2, ax2 = plt.subplots(1, 1) off = [2, 4, 8] ax2.plot(off, IP2.T, '-o', label=[f"IP ab={a}" for a in ab]) ax2.plot(off, Q2.T, '-o', label=[f"Q ab={a}" for a in ab]) ax2.set_title('DUALEM-842') ax2.set_xlabel('Offset (m)') ax2.set_ylabel('IP or Q (ppt)') ax2.legend() .. image-sg:: /gallery/fdomain/images/sphx_glr_ipandq_002.png :alt: DUALEM-842 :srcset: /gallery/fdomain/images/sphx_glr_ipandq_002.png :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 144-145 .. code-block:: Python empymod.Report() .. raw:: html
Sat Jan 17 19:14:46 2026 UTC
OS Linux (Ubuntu 22.04) CPU(s) 2 Machine x86_64
Architecture 64bit RAM 7.6 GiB Environment Python
File system ext4
Python 3.11.12 (main, May 6 2025, 10:45:53) [GCC 11.4.0]
numpy 2.3.5 scipy 1.17.0 numba 0.63.1
empymod 2.5.4.dev4+g4866dc83a libdlf 0.3.0 IPython 9.9.0
matplotlib 3.10.8


.. rst-class:: sphx-glr-timing **Total running time of the script:** (0 minutes 0.863 seconds) **Estimated memory usage:** 193 MB .. _sphx_glr_download_gallery_fdomain_ipandq.py: .. only:: html .. container:: sphx-glr-footer sphx-glr-footer-example .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: ipandq.ipynb ` .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: ipandq.py ` .. container:: sphx-glr-download sphx-glr-download-zip :download:`Download zipped: ipandq.zip ` .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_