# Calc_Area

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

Date 18-Mar-2014

Department of Land Air and Water

University of California Davis

## 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
```