James Badger’s Personal Site
DMS and Radians
Posted James on March 6th, 2006 | Filed under Development, Local Talk
I didn’t have a calculator for converting from radians to Degrees Minutes Seconds (e.g. 34-55-04), and also in the opposite direction. Initially, I thought I would do this with PHP, but I could do it instantaneously with Javascript instead. Feel free to give it a try, if you enter an approximation of π/2 ≅ 1.570796, you will get a value close to 90˚.
DMS to Radians Calculator
DMS – Wikipedia
July 25th, 2007 at 12:03 pm
it’s broken for negative radians
August 15th, 2009 at 8:27 am
That would be because negative radians, technically, do not exist. In the application of map coordinates, for example, negative radians are the way by which you distinguish north coordinates from south coordinates and east coordinates from west coordinates. Think of it as a grid system. 3 to the left of the X axis is the same distance as 3 to the right, just in the opposite direction.
Essentially, the negative sign is irrelevant, as far as the numbers are concerned, until you need to specify in which direction from the axis you need to be going.
August 15th, 2009 at 9:21 am
I must correct myself – I was thinking of decimal degrees in my previous comment, not radians.
The logic is the same, though.
The negative sign on a radian value (say, -X rad) is merely stating that you measure a value of X radians clockwise from 0. Radians are generally measured counter-clockwise from the 0 point, so a negative radian is just that many radians clockwise instead of in the normal direction. On a circle, you’d measure negative values down from zero instead of up. Either way, when converting the numbers themselves, disregard the negative symbol.
Hope that helps.