Nicolaas Kruik, Dutch astronomer and cartographer (b. 1678)
Nicolaas Samuelszoon Kruik (Latin: Nicolaus Samuelis Cruquius; 2 December 1678, West-Vlieland – 5 February 1754, Spaarndam), also known as Klaas Kruik and Nicolaes Krukius, was a Dutch land surveyor, cartographer, astronomer and weatherman. He is commemorated by the Museum De Cruquius.

He was a perfectionist who liked to measure things and he calculated temperature measurements in Fahrenheit from 1706 to 1734. His historical calculations are still used today by the KNMI, the Dutch meteorological institute. He not only measured weather changes in wind speed, rainfall, air pressure, temperature, and humidity, but also measured sea level. His method of visualising planes of water level to illustrate contours of depth (isobaths) in his map of the Merwede (1728) was the first of its kind. He was an advocate of pumping out the Haarlemmermeer (Haarlem lake), which was done a century after his death.