Introduction to grading of aggregates on concrete

Hydrographical Surveying

Hydrographical survey belongs to the science of measurement and explanation of features which impact maritime navigation, marine construction, dredging, offshore oil exploration/offshore oil drilling and relevant activities. Astronomical Surveying

An astronomical survey refers to a general map or image of a area of the sky which requires a definite observational target. On the other hand, an astronomical survey may contain a set of various images or spectra of objects which contribute to a common type or feature. To get more detailed information, watch the following video tutorial.