Although conducting 2D and 3D surveys manually with LandMapper is tedious and time-consuming, some of our customers (after gaining proficiency in 2D Dipole-Dipole tomography) have asked us about 3D survey.
Ideally, a 3-D survey should be carried out using a rectangular grid of electrodes with measurements in different directions (Loke and Barker 1996). However, for practical reasons (and certainly more so with manually switching instruments, such as LandMapper), most commercial 3-D surveys use a number of parallel 2-D survey lines with possibly some tie lines in a perpendicular direction.
The simplest layout combines three or more parallel 2D .dat files into 3D layout to run RES3DINV inversion and obtain 3D model of the subsurface.
Workflow:
- Conduct at least 3 parallel 2D lines surveys as described in LandMapper manual.
- Prepare 3 .dat files to import into RES2DINV (demo version should suffice).
- Create .txt file for collating lines into 3D file as described below
- Run RES3DINV on the newly created file. Demo version of RES2DINV and RES3DINV should be enough for the small amount of data typically collected with LandMapper.
More details are included in attached PDF.Collate data into RES3DINV format
See also CourseNotes by Dr.Loke and Res2dinvx64 / Res3dinvx64 user manuals.