ISOPLETH

The term isopleth has been derived from greek word isos meaning same and  plethron meaning measure . Thus isopleths are lines joining places of equal value.This value may be in the form of quantity, intensity or density

 Following are few examples of isopleths

Isobar :equal pressure .

Isotherms:equal temperature

Isohyet -equal rainfall

Isohaline :equal salinity

Sometimes, the space between isospleths are shaded or coloured whose intensity increases with the increase in value .this bring in more clarity of distribution.

Isopleth are used to show the following :

-climatic elements

-temperature

-pressure

-cloudiness

 While showing density of population and distribution of crops etc. care should be taken to show the index of concentration before actually plotting them on the map.

 

Merits

1. Isopleth are more scientific than other methods of showing distribution and effectively show the distribution and variations.
2. This is especially useful for climatic maps such as isobars, isotherms , isohyet etc.and is known as the main tool for the meteorologists
3. It is very easy to determine the gradient  (rate of change )with the help of isopleth maps.
4. When isopleth are wide apart ,they show low gradient but when they are closer  together they show high gradient .
5. Isopleth lines are independent of political boundaries and best suitet to show the natural pattern of distribution of an element .
6. isopleth is the most suited method for showing elements having transitional values ,this is a reason that isopleth are invariably used to show the distribution of temperature ,pressure and other climatic elements .

Demerits

     1.The drawing of isotherm often needs interpolation ,which is a difficult process.

    2.The method often suffers from lack of sufficient data.