大地测量学，根据德国大地测量学家F·R·Helmert的经典定义，它是一门量测和描绘地球表面的学科，也包括确定地球重力场和海底地形。

大地测量学起源于土地的划分与地产的界定，其历史可以追溯到古埃及时代。

公元前240年，亚历山大学者埃拉托斯特尼进行了亚历山大城和赛尼城（Syene，今阿斯旺）间的大地测量工作。当日光直射赛尼城井底时，在亚历山大城日光南偏7度12分，若假设日光彼此平行，则可估计地球周长为252.000古埃及尺。11世纪阿拉伯帝国和纽伦堡的测量仪器的发展对大地测量学的发展具有十分重要的意义，同样重要的还有角度函数的发现及荷兰科学家威理博·斯涅尔首创的三角测量法。

Geodesy (/dʒiːˈɒdᵻsi/), — also known as geodetics or geodetics engineering — a branch of applied mathematics and earth sciences, is the scientific discipline that deals with the measurement and representation of the Earth, including its gravitational field, in a three-dimensional time-varying space. Geodesists also study geodynamical phenomena such as crustal motion, tides, and polar motion. For this they design global and national control networks, using space and terrestrial techniques while relying on datums and coordinate systems.