[R] subtracting degree minutes

David L Carlson dcarlson at tamu.edu
Thu Jun 26 23:43:09 CEST 2014

This probably doesn't count as simple, but you can convert your format, call it degrees.minutes, to decimal degrees, do the math and then convert back. The functions would be simple:

dm2dd <- function(x) trunc(x) + (x - trunc(x))/60*100
dd2dm <- function(x) trunc(x) + (x - trunc(x))*60/100

So your problem would be 

> dd2dm(dm2dd(44.1) - dm2dd(.2))
[1] 43.5

Of course you could wrap that into a function if you are planning to do it frequently.

David L Carlson
Department of Anthropology
Texas A&M University
College Station, TX 77840-4352

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Trevor Davies
Sent: Thursday, June 26, 2014 2:43 PM
To: r-help at r-project.org
Subject: [R] subtracting degree minutes

Is there a simple way to subtract base-60 (coordinate system) values?

A trivial example:
I have a Lat of 44.1 degrees and I want to subtract 0.2 degrees from it.
 Therefore the answer should be 43.5 degrees (base 60).

I can do a change to character; stringsplit ; change back - deal with the
leading zeros but there must be an easier way.  (?)

Thanks for the help.

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