The resistors on the SPI bus are placed in a manner where they are located close to the source driver of the trace. In case of the SPI bus here one of the drivers (SDO) is located in the TDC1000 whilst the others are in the master device. The three resistors for the master belong over close to the master driver outputs.
These resistors are used to match the driver output impedance to the trace impedance so as to optimize the signal integrity of the waveform. As a rule of thumb the value of the resistor plus the actual output impedance of the driver should be equal to the trace impedance. Typical resistor values could range from 10 ohms to 50 ohms. That said there could be requirement for different values based upon the actual trace impedance and the routing topology. Trace impedance is determined by trace width, board stackup definition and adjacency to other traces. The resistor is typically selected to minimize reflections on the trace and limit ringing at the signal edges. At the same time trying to ensure that edge transitions are smooth and monotonic.
Small physical size resistors of the SMT type are the most ideal type of resistor to use for these. They eliminate the need for extra vias and through holes. I find that the 0402 size work well as a trade off with the modern pin pitch on packages and the typical artwork design rules used today. The really ideal situation is to have the connection from the driver to the resistor be short and without any intervening vias.