EarthImager 2D software

Features:

• Resistivity and IP inversion.
• ERT (electrical resistivity tomography) between two or more boreholes and surface electrodes.
• Borehole IP data inversion.
• Time lapse resistivity inversion for monitoring applications both on the surface and in the boreholes (upgrade).
• Survey planner with graphical model input, virtual survey with the actual command file, and inverse simulation with user-specified Gaussian noises.
• Topographic correction and printout of resistivity section with topographical features.
• Finite difference and finite element forward modeling.
• Options of boundary condition for forward modeling.
• Three inversion algorithms: damped least squares, smooth model, and robust inversion.
• Three IP data inversion methods: linear, nonlinear-concurrent, and nonlinear-sequential inversion methods.
• Gauss-Newton and quasi Newton methods.
• User friendly Windows GUI.
• Fast graphics powered by OpenGL with automatic refresh and scalable image.
• Real time scrolling through all iterations using the mouse wheel, creating "movie like" animation.
• Data editing for detecting and removing erroneous data points and bad electrodes.
• Noisy data suppression.
• Both root mean squared (RMS) error and L2-norm statistics to monitor the inversion progress and convergence.
• No software limit on number of data or number of electrodes.
• No limit on array type or electrode location.
• A graphical a-priori information input interface.
• Seamless operation with AGI resistivity instruments.
• Removable contour curves and automatic blanking.
• Windows true type font and true 24-bit color.
• Trackable and retrievable user settings.
• Tool buttons and popup menus for easy access to frequently used menu items.
• Inversion progress bar to show the inversion status.
• Well organized and hassle-free processing directory structure.
• Automatic file saving feature with on/off options.
• Retrievable inversion output/log file.
• High definition report quality plat style printout.
• Saving images as bitmap, JPEG or Windows metafile files at three resolution levels.
• Saving image data in XYZ format so it can be loaded into any off-shelf graphics software.
• Check of computer memory status to estimate processing capability.
• Borehole command creator for AGI Sting/SuperSting instruments.
• Support of competitor's data file format.
• Data misfit scatter plot and cross-plot
• Convergence curve
• Reversal and horizontal shift of a profile.
• Batch inversion of many data files

2D Resistivity Inversion
Reads Sting data (and other instrument data formats) and produces a default setting inversion, valid in most cases, after only a few clicks. For advanced processing there are a number of settings for full user control of the inversion process. Report ready high definition graphic output in the form of engineering plate style drawing with title block.

2D Electrical Resistivity Tomography (ERT)
The software automatically detects bore hole data set for immediate ERT processing. There is an editor for “bad” electrode and “bad” data removal. From iteration to iteration the data misfit is displayed in a scatter plot. There is also a data cross plot (raw versus inverted apparent resistivity data) available as well as a diagram showing the convergence curve.

Time Lapse Option
The optional Time Lapse function is used for any monitoring situation. It could for example be used to detect leakage at a landfill site. In such a case, the resistivity image is first recorded as "background" (before any leakage). After the initial "background" setup, the survey is repeated at regular intervals in the same way (electrodes in the same place using the same array type, etc.) so that any change in the ground can be detected. The time lapse function uses the inverted background section when inverting the "new" section and the result is presented as the difference between the two sections.
The time lapse method is used any time information about resistivity changes in the ground is needed. Some common situations include potential leakage from landfills, industrial sites, etc. Other monitoring situations include fracture tracing by injection of a conductive solution such as a salt solution. Other possible monitoring situations include saltwater intrusion in coastal areas, remediation progress at environmental sites, groundwater recharge, infiltration studies, to see how the ground is "wetted" or how the ground dries up after a rain storm.

Survey Planner
The survey planner is used for feasibility studies of resistivity imaging projects. First load a command file, then enter the expected geological features with their expected resistivities in a graphical input interface. Then run the simulation using the actual command file and the software will perform a virtual survey over the theoretical model. The result of the virtual survey is then inverted and the result can be compared to the original model within seconds.

Topography Correction
In case of terrain relief it may be necessary to include topography correction in the inversion process. Data with terrain elevation is read from a “terrain file “ and the software will automatically perform an inversion using a finite element model.