A method for determining formation resistivity, anisotropy and dip from wellbore measurements made using a well logging instrument including electromagnetic transmitters and receivers oriented as longitudinal magnetic dipoles, and tilted magnetic dipoles and/or transverse magnetic dipoles, the transmitters and receivers used to make corresponding dipole sensitive measurements, the method comprising: moving the well logging instrument through subsurface formations and making corresponding dipole sensitive measurements; inverting the measurements using a substantially planar, parallel bedded, transversely isotropic formation model, the inversion including the steps of: determining formation layer boundaries of the formation layers from the longitudinal magnetic dipole measurements; determining horizontal resistivities of the formation layers from the longitudinal magnetic dipole measurements; and determining vertical resistivities of the formation layers by inversion of anisotropy sensitive electromagnetic measurements; characterized in that the inversion further includes: determining improved vertical resistivities of the formation layers and dips thereof by inverting symmetrized and anti-symmetrized electromagnetic measurements; determining improved vertical resistivities, improved layer boundaries and improved dips by inversion of the longitudinal magnetic dipole, anisotropy sensitive, symmetrized and anti-symmetrized measurements; determining improved horizontal resistivities, further improved layer boundaries and further improved dips by inversion of the longitudinal magnetic dipole, anisotropy sensitive, symmetrized and anti-symmetrized measurements; and examining the misfit between the inverted measurements and the model. moving the well logging instrument through subsurface formations and making corresponding dipole sensitive measurements; inverting the measurements using a substantially planar, parallel bedded, transversely isotropic formation model, the inversion including the steps of: determining formation layer boundaries of the formation layers from the longitudinal magnetic dipole measurements; determining horizontal resistivities of the formation layers from the longitudinal magnetic dipole measurements; and determining vertical resistivities of the formation layers by inversion of anisotropy sensitive electromagnetic measurements; determining formation layer boundaries of the formation layers from the longitudinal magnetic dipole measurements; determining horizontal resistivities of the formation layers from the longitudinal magnetic dipole measurements; and determining vertical resistivities of the formation layers by inversion of anisotropy sensitive electromagnetic measurements; characterized in that the inversion further includes: determining improved vertical resistivities of the formation layers and dips thereof by inverting symmetrized and anti-symmetrized electromagnetic measurements; determining improved vertical resistivities, improved layer boundaries and improved dips by inversion of the longitudinal magnetic dipole, anisotropy sensitive, symmetrized and anti-symmetrized measurements; determining improved horizontal resistivities, further improved layer boundaries and further improved dips by inversion of the longitudinal magnetic dipole, anisotropy sensitive, symmetrized and anti-symmetrized measurements; and examining the misfit between the inverted measurements and the model. determining improved vertical resistivities of the formation layers and dips thereof by inverting symmetrized and anti-symmetrized electromagnetic measurements; determining improved vertical resistivities, improved layer boundaries and improved dips by inversion of the longitudinal magnetic dipole, anisotropy sensitive, symmetrized and anti-symmetrized measurements; determining improved horizontal resistivities, further improved layer boundaries and further improved dips by inversion of the longitudinal magnetic dipole, anisotropy sensitive, symmetrized and anti-symmetrized measurements; and examining the misfit between the inverted measurements and the model.