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# What is Thiessen polygon method used for?

## What is Thiessen polygon method used for?

The Thiessen polygon (Figure T5) is a commonly used methodlogy for computing the mean areal precipitation for a catchment from raingauge observations which was presented by A.H. Thiessen (1911).

## Why is Isohyetal method the most accurate?

Answer: The isohyetal method is considered to be more accurate than the Thiessen polygon method or gridpoint technique to estimate rainfall totals because it includes the effects of local features.

What is Thiessen polygon interpolation?

Thiessen polygons, also referred to as Dirichlet tessellations or Voronoi diagrams, are an exact method of interpolation that assumes that the values of unsampled locations are equal to the value of the nearest sampled point.

What are 3 ways to measure precipitation?

Measuring rainfall can be is primarily done in three different ways using three different types of rain gauges. The three major types of rain gauges are the standard gauge, tipping bucket gauge and weighing gauge.

### What is Thiessen polygon in GIS?

From wiki.gis.com. Based on an area containing at least two points, a Thiessen Polygon is a 2-dimensional shape whose boundaries contain all space which is closer to a point within the area than any other point without the area.

### What is Isohyetal method used for?

The isohyetal method is used to estimate the mean precipitation across an area by drawing lines of equal precipitation. The method uses topographic and other data to yield reliable estimates. Isohyets are contours of equal precipitation analogous to contour lines on a topographic map.

What are Thiessen weights?

In the Thiessen method station weights are determined in proportion to their representative areas defined by a polygon. The polygons are formed from bisectors of the station interconnections around the stations and/or the catchment boundary.

What is point rainfall measurement?

[′pȯint ′rān‚fȯl] (meteorology) The rainfall during a given time interval (or often one storm) measured in a rain gage, or an estimate of the amount which might have been measured at a given point.

## Why do we need Thiessen polygon interpolation?

The Thiessen polygon method is usually used to detect the average rain height if the rain station is not evenly distributed. Thiessen’s polygon is also one of the local interpolation methods. This method is also called the proximal method, i.e. an attempt to weight the data points in an area.