Dr. Chris Kirtley

01-03-2003, 02:46 AM

Happy new year to all.

Before I forget, I want to thank everyone who replied about the 2D angle

calculation problem. I have collated all the responses here:

http://guardian.curtin.edu.au/cga/faq/2Dangles.html

With the risk of offending everyone else, I am going to give my prize to

Zia Hasan, who came up with the following very simple algorithm:

IF x not equal to zero THEN angle = ATN(y/x) ELSE angle = SGN(y) * pi /

2

IF x < 0 THEN angle = angle + pi

IF angle < 0 THEN angle = angle +2*pi

I have checked this out for angles from 0 to 315 in steps of 45 degrees

in this little Excel spreadsheet:

http://guardian.curtin.edu.au/cga/faq/2Dangles.xls

As you can see, it works nicely. This might be a nice addition to the

ISB Software Archive.

Thanks again to everyone, and especially to Zia!

Chris

--

Dr. Chris Kirtley MD PhD

Associate Professor

Dept. of Biomedical Engineering

Catholic University of America

620 Michigan Ave NE, Washington, DC 20064

Tel. 202-319-6247, fax 202-319-4287

Email: kirtley@cua.edu

http://engineering.cua.edu/biomedical/faculty/kirtley

---------------------------------------------------------------

To unsubscribe send SIGNOFF BIOMCH-L to LISTSERV@nic.surfnet.nl

For information and archives: http://isb.ri.ccf.org/biomch-l

---------------------------------------------------------------

Before I forget, I want to thank everyone who replied about the 2D angle

calculation problem. I have collated all the responses here:

http://guardian.curtin.edu.au/cga/faq/2Dangles.html

With the risk of offending everyone else, I am going to give my prize to

Zia Hasan, who came up with the following very simple algorithm:

IF x not equal to zero THEN angle = ATN(y/x) ELSE angle = SGN(y) * pi /

2

IF x < 0 THEN angle = angle + pi

IF angle < 0 THEN angle = angle +2*pi

I have checked this out for angles from 0 to 315 in steps of 45 degrees

in this little Excel spreadsheet:

http://guardian.curtin.edu.au/cga/faq/2Dangles.xls

As you can see, it works nicely. This might be a nice addition to the

ISB Software Archive.

Thanks again to everyone, and especially to Zia!

Chris

--

Dr. Chris Kirtley MD PhD

Associate Professor

Dept. of Biomedical Engineering

Catholic University of America

620 Michigan Ave NE, Washington, DC 20064

Tel. 202-319-6247, fax 202-319-4287

Email: kirtley@cua.edu

http://engineering.cua.edu/biomedical/faculty/kirtley

---------------------------------------------------------------

To unsubscribe send SIGNOFF BIOMCH-L to LISTSERV@nic.surfnet.nl

For information and archives: http://isb.ri.ccf.org/biomch-l

---------------------------------------------------------------