Surveyor. Born at Carluke (South Lanarkshire), Thomson and his mother emigrated to New Zealand, arriving in New Zealand in 1874. He joined the New Zealand Lands and Survey Department there in 1883 and after training he was to revise some of the early surveys around Hawkes Bay. From 1889 he surveyed settlements and roads in the Poverty Bay district. Following the 1892 Land Act, he was involved in the subdivision of new Crown in Southland, Otago and Canterbury.
In 1899, came one of his most significant contributions when he was jointly responsible for initiating the Magnetic Survey of New Zealand. He went on to initiate the first thorough contour survey in the country. In 1901 he was appointed District Surveyor at Dunedin and was able to carry out the standard survey of the city.
In 1918 he was appointed Chief Inspector of Surveys in Wellington and in 1920 was promoted to become Surveyor General of New Zealand. He retired in 1929.
Neill was twice able to travel abroad to examine the latest survey methods being used; in 1890 he travelled to Australia while, in 1908, he was able to visit Canada, the USA and the Europe.
In addition to his technical skills, Neill published on issues relating to his work both in New Zealand and beyond.
He died in Wellington.