# Calc_Area

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Computes the area of 2D mesh elements in a vectorized manner. It workds for triangular and quadrilateral elements of any order. However the sides of the elements must be striaght lines otherwise the calculation will be wrong.

Version : 1.0

Author : George Kourakos

email: giorgk@gmail.com

web : http://groundwater.ucdavis.edu/msim

Date 18-Mar-2014

Department of Land Air and Water

University of California Davis

## Contents

## Usage

A = Calc_Area(p, MSH);

## Input:

* p* : [Np x 2] coordinates

* MSH* : [Nel, Nsh] Mesh element ids. Nel is the number of elements and Nsh is the number of shapefunctions. The ids correspond to the row of the array

**p**## Output

* A* : [Nel x 1] The area of each element.

## Example

Create a hypothetical mesh

p = 10 * rand(10,2); MSH = delaunay(p(:,1), p(:,2));

Calculate the area of each element

A = Calc_Area(p, MSH);

Calculate the barycenter of each element

cc = Calc_Barycenters(p,MSH);

Display the area of each element

triplot(MSH, p(:,1), p(:,2)) hold on for i = 1:size(cc, 1) text(cc(i,1),cc(i,2),num2str(A(i,1)),'HorizontalAlignment','center') end