Finding the area of a polygon.

Hi I have a set of x and y coordinates which form the corners of a polygon. I need to calculate area manually using the shoelace formula as illustrated below.

I need to do this way of multiplying to get two vectors using vectorization. I am not sure of how I would write code for this. It needs to be so that if the amount of corners increased or there values their values changed this would be accounted for.

Thanks,

Answer 1

[Sean de Wolski]

>> edit polyarea

Look at the code, it implements the surveyor's formula that you have.

Answer 2

[Image Analyst]

Is this homework, where you need to use that? Otherwise, just use the built in polyarea() function.

[Giuseppe]

I have an assignment where I need to formulate a method to come up with the area of any simple polygon. I am using this method. We have been told we cant use polyarea().

[Image Analyst]

You should have tagged it as homework then, but I did it for you. So, first read this: http://www.mathworks.com/matlabcentral/answers/8626-how-do-i-get-help-on-homework-questions-on-matlab-answers then show how you made some nested for loops to do the multiplication and ask for help. But you need to do something first. We can't just hand over a turnkey homework solution to you.