Electrical resistivity tomography# 2D ERT modelling and inversion 2D ERT modelling and inversion ERT field data with topography ERT field data with topography 2D FEM modelling on two-layer example 2D FEM modelling on two-layer example Geoelectrics in 2.5D Geoelectrics in 2.5D Four-point sensitivities Four-point sensitivities 2D crosshole ERT inversion 2D crosshole ERT inversion ERT inversion of data measured on a standing tree ERT inversion of data measured on a standing tree 3D surface ERT inversion 3D surface ERT inversion 3D crosshole ERT inversion 3D crosshole ERT inversion Timelapse ERT Timelapse ERT Reciprocal data analysis of field ERT data Reciprocal data analysis of field ERT data 3D modelling in a closed geometry 3D modelling in a closed geometry