Hypsometric Levelling in Surveying
In this article, we will see about Hypsometric Levelling, which is useful to understand for Civil Engineers.
So, let's see,
What is Hypsometric Levelling?
Hypsometric Levelling is a type of levelling in Surveying in which we determine height and altitude using the fact that boiling of water depends upon atmospheric pressure applied to water at that time.
As the height increases, pressure at that level decreases, and correspondingly water boiling happens also get affected. By measuring pressure and temperature at which water boils, we can estimate what should be difference of heights or elevation between it should have.
Formula showing relationship between Temperature, Pressure and Volume:
PV = nRT
By this formula, and some other formulas, we can understand, if height increases, then Pressure at that height decreases, and also Temperature required for Boiling of Water decreases.
As temperature required for Boiling decreases, more water can evaporates, boiling can happens fast. So, when we are on great height, water should boil fast. And vice versa, when we are near to surface of earth, water should boil slow.
As relationship is linear, we can note down current temperature and pressure, and some other parameters required for formula. Also, parameters of reference level, and by some calculation, we can find estimated Elevation.
Is Hypsometric Levelling Direct method or Indirect Method of Levelling?
Hypsometric Levelling is an indirect method of levelling.
As, for levelling, there are various methods which can primarily divided into two types:
- Direct method
- Indirect Method
In the Direct, we find levelling directly from some instruments. And in the Indirect Methods, we estimates heights or levels using some formulas, trigonometry or other ways that do not directly involves measuring of exact heights by Instrument.
Comments
Post a Comment