Analysis of information sources in references of the Wikipedia article "ไร่" in Thai language version.
It so happens that 40 metres or 4,000 centimetres are equal to one sen, so all cadastral plans are plotted, drawn, and printed to a scale of 1:4,000.
It so happens that 40 metres or 4,000 centimetres are equal to one sen, so all cadastral plans are plotted, drawn, and printed to a scale of 1:4,000.