This chapter explores the local control of thermoelectric properties in layered nanostructures, with a particular emphasis on the Seebeck coefficient. The goal of this chapter is to demonstrate how nanoscale modifications, specifically nanoconstrictions, can be used to spatially tune thermovoltage generation and enable in situ characterisation of thermoelectric (TE) behaviour. The chapter introduces scanning thermal gate microscopy (STGM) as a central technique, allowing precise probing of local thermovoltage responses. After describing the experimental setup and the underlying conversion principles, the focus shifts to two types of patterned nanoconstrictions: bow tie geometries in encapsulated graphene and hole arrays in tin diselenide. These engineered structures enable the manipulation of local electronic and thermal transport, directly impacting the Seebeck coefficient and the resulting thermoelectric response. The final section addresses thickness-induced thermoelectric boundaries in graphite, further illustrating how structural parameters can be harnessed to control TE behaviour. Together, these studies highlight the potential of 2D materials for nanoscale thermoelectric applications and establish a methodology for achieving spatial control over energy conversion at the device level. The techniques and results presented here lay the foundation for future strategies in designing thermoelectric platforms with locally optimised performance.