Isohyet
Topic: Graphical Representation of Data and Thematic Maps · NCERT: Class 12, Ch 3 "Graphical Representation of Data"
Meaning
An isohyet is an isopleth, a line joining places of equal value. It joins places that get the same amount of rainfall over a set period, such as a year or a season. It is drawn from rain-gauge readings by interpolation, which means estimating the values between gauges. An isohyet map shows the pattern of rainfall at a glance: where it is heavy, where it is scanty, and how sharply it changes. IMD rainfall maps use isohyets.
Example
On India's annual rainfall map, the 200 cm isohyet encloses the Western Ghats coast and the north-east, including Meghalaya. The 50 cm isohyet marks off the dry west of Rajasthan.
Don't confuse with
- An isotherm joins places of equal temperature.
- An isoneph joins places of equal cloudiness, and an isohel joins places of equal sunshine. Neither one measures rainfall.