```Path: news.mathworks.com!not-for-mail
From: "John D'Errico" <woodchips@rochester.rr.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: 2-d numerical integration
Date: Mon, 30 May 2011 16:10:20 +0000 (UTC)
Organization: John D'Errico (1-3LEW5R)
Lines: 19
Message-ID: <is0fhc\$lps\$1@newscl01ah.mathworks.com>
References: <is0cmq\$fbf\$1@newscl01ah.mathworks.com>
NNTP-Posting-Host: www-03-blr.mathworks.com
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
X-Trace: newscl01ah.mathworks.com 1306771820 22332 172.30.248.48 (30 May 2011 16:10:20 GMT)
X-Complaints-To: news@mathworks.com
NNTP-Posting-Date: Mon, 30 May 2011 16:10:20 +0000 (UTC)
Xref: news.mathworks.com comp.soft-sys.matlab:729312

"Tomer Alon" <tomeralon112@gmail.com> wrote in message <is0cmq\$fbf\$1@newscl01ah.mathworks.com>...
> hi, i have a question about 2-d integral.
> i have a matrix for x,y,data and i can't express my data as a function.
> how can i do an integral on the data with respect to the x,y points?
> thanks for the helpers

You cannot integrate points. Points, shmoints. Well,
you can integrate over them, but it is a set of measure
zero, so a rather boring result.

You can integrate a function. So you need to define
a domain. You need to find a function that approximates
or interpolates those points. Then integrate that function
over the indicated domain. This may involve a triangulation
of the domain from these points. If the domain is not
convex, then the triangulation will be more difficult.

HTH,
John
```