Re: [R] Changing sign on absolute numbers 0 problems
Sadz A sadz_a1...@yahoo.co.uk wrote in message news:419230.77523...@web24610.mail.ird.yahoo.com... Hi, I am trying to do some calculations turning DMS data to decimal degrees using the formula (D+(M/60)+(S/3600)), some of the D's involve -ve numbers, the easiest way to do the calculation is to use absolute numbers then use the 'sign' function in R to change the answer back to the correct -ve or +ve, for example, if; D--69 M-8 S-10 then decimal-D+(M/60)+(S/3600) -69+(8/60)+(10/3600) = this would equal -68.86389 (which is wrong, it should be -69.13611, so i used the following function) decimal-(abs(D)+(M/60)+(S/3600)) decimal.degs-sign(D)*decimal decimal.degs -69.13611 because ((69+(8/60)+(10/3600)=69.13611) and then the -sign is put back in. This works fine untill D=0 because then 'sign' does not give 0 a +ve sign it takes it as 0 and multiplies decimal by 0 to give 0. example D-0 decimal-D+(M/60)+(S/3600) decimal.degs-sign(D)*decimal decimal.degs 0 Is there anyway to get around this?? and make D=0 a positive and not a 0 with sign or another function?? Any help is appreciated Thank you sadz ps please email me if you need more info [[alternative HTML version deleted]] In addition to the other comments, you might be interested in package 'sp' which has: Class DMS for degree, minute, decimal second values and facilities to convert between DMS, decimal, and character. HTH Keith J __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Changing sign on absolute numbers 0 problems
With permission I am copying a private communication to the list.
On Oct 21, 2010, at 9:20 AM, Sadz A wrote:
Hi,
I think maybe I did not explain myself properly, I'll try again;
I am trying to convert location data in DMS degrees to decimal
degrees format.
I have attached my data and below is the work I have done so far and
notes explaining what I have done. The problem is negative 0, the
+/- sign indicates direction so it is very important to have the
right sign in front, but R takes 0 and -0 as 0.
#approach
#download 'gsubfn' from R CRAN.
#please insert appropriate directory, the table is attached#
data-read.table(vol by genous lat lon.txt,header=T)
names(data)
attach(data)
library(gsubfn)
#the latitude data is in MD_LATITUD so to separate out the numbers
and convert to decimal degrees i used...
At this point I realized that my earlier assumption that -0 == 0 might
not be as obvious as I had thought, at least when it applies to the
leading degrees entry in a latitude, which I was not thinking about
very clearly.
latitude-as.vector(MD_LATITUD)
x - c(latitude)
Convert - function(d, m, s, dd = as.numeric(d), mm = as.numeric(m),
ss = as.numeric(s)) sign(dd) * (abs(dd) + mm / 60 + ss / 3600)
The problem as I saw it was that the as.numeric conversion of d to dd
was throwing away the sign.
test - c(-0:00:53, -0:01:10., -0:01:26., -0:01:38., -0:01:43,
-0:01:59., -0:03:50., -0:04:46, -0:05:01., -0:05:16.,
3:41:33.0, 3:43:09.4, 3:44:26.3, 3:47:26.0, 3:48:19.3,
3:52:13.4, 3:57:10.2, 4:29:37.6, 5:01:28.4, 5:08:45.6 )
So I substituted an ifelse( grepl(d) -1,1) test for - from the
unconverted degree entry:
Convert - function(d, m, s, dd = as.numeric(d), mm = as.numeric(m),
ss = as.numeric(s)){
ifelse(grepl(-, d),-1,1) * (abs(dd) + mm /
60 + ss / 3600) }
Lat-strapply(test, (.*):(.*):(.*), Convert, simplify = TRUE)
Lat
[1] -0.0147 -0.0194 -0.0239 -0.0272 -0.0286
-0.03305556 -0.0639 -0.0794
[9] -0.0836 -0.0878 3.6925 3.71927778 3.74063889
3.7906 3.80536111 3.87038889
[17] 3.9528 4.4938 5.0246 5.1460
Lat-strapply(x, (.*):(.*):(.*), Convert, simplify = TRUE)
Lat
#as you can see in Lat there are lots of 0's, which should not be
there but are because 'sign(dd)' takes +ve when +ve, -ve when -ve
and multiplies it by 'abs(dd)' which is correct, BUT for 0 it
assigns niether +ve or -ve, giving 0 a 0, and anything times 0 is
0..
#I modified the code to
latitude-as.vector(MD_LATITUD)
x - c(latitude)
Convert - function(d, m, s, dd = as.numeric(d), mm = as.numeric(m),
ss = as.numeric(s)) sign(ifelse(dd==0,sign(dd))) * (abs(dd) + mm /
60 + ss / 3600)
Lat-strapply(x, (.*):(.*):(.*), Convert, simplify = TRUE)
Lat
#so I now have the correct absolute decimal degrees in all cases and
the correct direction in all cases except where there should be a
-0!, because -0's are ignored and assumed to be the same as +0 which
is wrong because the + and - indicate direction.
# Do you know of a way I can get R to separate out the sign from
MD_LATITUD, so that I can change
# 'Convert - function(d, m, s, dd = as.numeric(d), mm =
as.numeric(m), ss = as.numeric(s)) sign(dd) * (abs(dd) + mm / 60 +
ss / 3600)' to something like
# 'Convert - function(sign, d, m, s, dd = as.numeric(d), mm =
as.numeric(m), ss = as.numeric(s)) sign * (abs(dd) + mm / 60 + ss /
3600) #(this does not work but something similar, or a different
approach may?)
Any help will be appreciated.
Thank you
sadz
From: David Winsemius dwinsem...@comcast.net
To: David Winsemius dwinsem...@comcast.net
Cc: Sadz A sadz_a1...@yahoo.co.uk; r-help@r-project.org
Sent: Wed, 20 October, 2010 20:45:39
Subject: Re: [R] Changing sign on absolute numbers 0 problems
On Oct 20, 2010, at 3:19 PM, David Winsemius wrote:
On Oct 20, 2010, at 11:47 AM, Sadz A wrote:
Hi,
I am trying to do some calculations turning DMS data to decimal
degrees using
the formula (D+(M/60)+(S/3600)), some of the D's involve -ve
numbers, the
easiest way to do the calculation is to use absolute numbers then
use the 'sign'
function in R to change the answer back to the correct -ve or +ve,
for example, if;
D--69
M-8
S-10
then
decimal-D+(M/60)+(S/3600)
-69+(8/60)+(10/3600) = this would equal -68.86389 (which is
wrong, it should
be -69.13611, so i used the following function)
decimal-(abs(D)+(M/60)+(S/3600))
decimal.degs-sign(D)*decimal
decimal.degs
-69.13611
because ((69+(8/60)+(10/3600)=69.13611) and then the -sign is put
back in.
This works fine untill D=0
because then 'sign' does not give 0 a +ve sign it takes it as 0
and multiplies
decimal by 0 to give 0.
example
D-0
decimal-D+(M/60)+(S/3600)
decimal.degs-sign(D)*decimal
decimal.degs
0
Is there anyway to get around this??
I am not sure I understand the source of your distress
Re: [R] Changing sign on absolute numbers 0 problems
Thank you so much!
From: David Winsemius dwinsem...@comcast.net
Cc: r-help r-help r-help@r-project.org
Sent: Thu, 21 October, 2010 15:43:37
Subject: Re: [R] Changing sign on absolute numbers 0 problems
With permission I am copying a private communication to the list.
On Oct 21, 2010, at 9:20 AM, Sadz A wrote:
Hi,
I think maybe I did not explain myself properly, I'll try again;
I am trying to convert location data in DMS degrees to decimal degrees format.
I have attached my data and below is the work I have done so far and notes
explaining what I have done. The problem is negative 0, the +/- sign indicates
direction so it is very important to have the right sign in front, but R takes
0
and -0 as 0.
#approach
#download 'gsubfn' from R CRAN.
#please insert appropriate directory, the table is attached#
data-read.table(vol by genous lat lon.txt,header=T)
names(data)
attach(data)
library(gsubfn)
#the latitude data is in MD_LATITUD so to separate out the numbers and
convert to decimal degrees i used...
At this point I realized that my earlier assumption that -0 == 0 might not be
as
obvious as I had thought, at least when it applies to the leading degrees
entry in a latitude, which I was not thinking about very clearly.
latitude-as.vector(MD_LATITUD)
x - c(latitude)
Convert - function(d, m, s, dd = as.numeric(d), mm = as.numeric(m), ss =
as.numeric(s)) sign(dd) * (abs(dd) + mm / 60 + ss / 3600)
The problem as I saw it was that the as.numeric conversion of d to dd was
throwing away the sign.
test - c(-0:00:53, -0:01:10., -0:01:26., -0:01:38., -0:01:43,
-0:01:59., -0:03:50., -0:04:46, -0:05:01., -0:05:16.,
3:41:33.0, 3:43:09.4, 3:44:26.3, 3:47:26.0, 3:48:19.3,
3:52:13.4, 3:57:10.2, 4:29:37.6, 5:01:28.4, 5:08:45.6 )
So I substituted an ifelse( grepl(d) -1,1) test for - from the unconverted
degree entry:
Convert - function(d, m, s, dd = as.numeric(d), mm = as.numeric(m),
ss = as.numeric(s)){
ifelse(grepl(-, d),-1,1) * (abs(dd) + mm / 60 + ss /
3600) }
Lat-strapply(test, (.*):(.*):(.*), Convert, simplify = TRUE)
Lat
[1] -0.0147 -0.0194 -0.0239 -0.0272 -0.0286 -0.03305556
-0.0639 -0.0794
[9] -0.0836 -0.0878 3.6925 3.71927778 3.74063889 3.7906
3.80536111 3.87038889
[17] 3.9528 4.4938 5.0246 5.1460
Lat-strapply(x, (.*):(.*):(.*), Convert, simplify = TRUE)
Lat
#as you can see in Lat there are lots of 0's, which should not be there but
are
because 'sign(dd)' takes +ve when +ve, -ve when -ve and multiplies it by
'abs(dd)' which is correct, BUT for 0 it assigns niether +ve or -ve,
giving
0 a 0, and anything times 0 is 0..
#I modified the code to
latitude-as.vector(MD_LATITUD)
x - c(latitude)
Convert - function(d, m, s, dd = as.numeric(d), mm = as.numeric(m), ss =
as.numeric(s)) sign(ifelse(dd==0,sign(dd))) * (abs(dd) + mm / 60 + ss / 3600)
Lat-strapply(x, (.*):(.*):(.*), Convert, simplify = TRUE)
Lat
#so I now have the correct absolute decimal degrees in all cases and the
correct direction in all cases except where there should be a -0!, because
-0's
are ignored and assumed to be the same as +0 which is wrong because the + and
-
indicate direction.
# Do you know of a way I can get R to separate out the sign from MD_LATITUD,
so
that I can change
# 'Convert - function(d, m, s, dd = as.numeric(d), mm = as.numeric(m), ss =
as.numeric(s)) sign(dd) * (abs(dd) + mm / 60 + ss / 3600)' to something like
# 'Convert - function(sign, d, m, s, dd = as.numeric(d), mm = as.numeric(m),
ss = as.numeric(s)) sign * (abs(dd) + mm / 60 + ss / 3600) #(this does not
work
but something similar, or a different approach may?)
Any help will be appreciated.
Thank you
sadz
From: David Winsemius dwinsem...@comcast.net
To: David Winsemius dwinsem...@comcast.net
Sent: Wed, 20 October, 2010 20:45:39
Subject: Re: [R] Changing sign on absolute numbers 0 problems
On Oct 20, 2010, at 3:19 PM, David Winsemius wrote:
On Oct 20, 2010, at 11:47 AM, Sadz A wrote:
Hi,
I am trying to do some calculations turning DMS data to decimal degrees
using
the formula (D+(M/60)+(S/3600)), some of the D's involve -ve numbers, the
easiest way to do the calculation is to use absolute numbers then use the
'sign'
function in R to change the answer back to the correct -ve or +ve,
for example, if;
D--69
M-8
S-10
then
decimal-D+(M/60)+(S/3600)
-69+(8/60)+(10/3600) = this would equal -68.86389 (which is wrong, it
should
be -69.13611, so i used the following function)
decimal-(abs(D)+(M/60)+(S/3600))
decimal.degs-sign(D)*decimal
decimal.degs
-69.13611
because ((69+(8/60)+(10/3600)=69.13611) and then the -sign is put back in.
This works fine untill D=0
because then 'sign' does not give 0 a +ve sign it takes it as 0 and
multiplies
decimal
Re: [R] Changing sign on absolute numbers 0 problems
In case it helps...
test - c(-0:00:53, -0:01:10., -0:01:26., -0:01:38., -0:01:43,
+ -0:01:59., -0:03:50., -0:04:46, -0:05:01., -0:05:16.,
+ 3:41:33.0, 3:43:09.4, 3:44:26.3, 3:47:26.0, 3:48:19.3,
+ 3:52:13.4, 3:57:10.2, 4:29:37.6, 5:01:28.4, 5:08:45.6 )
require(sp)
as.numeric.DMS(char2dms(paste(sub($, '',sub(:, ',sub(:, d,
test))),ifelse(substring(test,1,1)==-,W,E), sep=)))
[1] -0.0147 -0.0194 -0.0239 -0.0272 -0.0286 -0.03305556
-0.0639 -0.0794 -0.0836
[10] -0.0878 3.6925 3.71927778 3.74063889 3.7906 3.80536111
3.87038889 3.9528 4.4938
[19] 5.0246 5.1460
David Winsemius dwinsem...@comcast.net wrote in message
news:9c5d0d83-2ceb-4f5c-a57e-c75fbbda9...@comcast.net...
With permission I am copying a private communication to the list.
On Oct 21, 2010, at 9:20 AM, Sadz A wrote:
Hi,
I think maybe I did not explain myself properly, I'll try again;
I am trying to convert location data in DMS degrees to decimal degrees
format.
I have attached my data and below is the work I have done so far and
notes explaining what I have done. The problem is negative 0, the +/-
sign indicates direction so it is very important to have the right sign
in front, but R takes 0 and -0 as 0.
#approach
#download 'gsubfn' from R CRAN.
#please insert appropriate directory, the table is attached#
data-read.table(vol by genous lat lon.txt,header=T)
names(data)
attach(data)
library(gsubfn)
#the latitude data is in MD_LATITUD so to separate out the numbers and
convert to decimal degrees i used...
At this point I realized that my earlier assumption that -0 == 0 might
not be as obvious as I had thought, at least when it applies to the
leading degrees entry in a latitude, which I was not thinking about very
clearly.
latitude-as.vector(MD_LATITUD)
x - c(latitude)
Convert - function(d, m, s, dd = as.numeric(d), mm = as.numeric(m), ss
= as.numeric(s)) sign(dd) * (abs(dd) + mm / 60 + ss / 3600)
The problem as I saw it was that the as.numeric conversion of d to dd was
throwing away the sign.
test - c(-0:00:53, -0:01:10., -0:01:26., -0:01:38., -0:01:43,
-0:01:59., -0:03:50., -0:04:46, -0:05:01., -0:05:16.,
3:41:33.0, 3:43:09.4, 3:44:26.3, 3:47:26.0, 3:48:19.3,
3:52:13.4, 3:57:10.2, 4:29:37.6, 5:01:28.4, 5:08:45.6 )
So I substituted an ifelse( grepl(d) -1,1) test for - from the
unconverted degree entry:
Convert - function(d, m, s, dd = as.numeric(d), mm = as.numeric(m),
ss = as.numeric(s)){
ifelse(grepl(-, d),-1,1) * (abs(dd) + mm / 60
+ ss / 3600) }
Lat-strapply(test, (.*):(.*):(.*), Convert, simplify = TRUE)
Lat
[1] -0.0147 -0.0194 -0.0239 -0.0272 -0.0286 -0.03305556
-0.0639 -0.0794
[9] -0.0836 -0.0878 3.6925 3.71927778 3.74063889
3.7906 3.80536111 3.87038889
[17] 3.9528 4.4938 5.0246 5.1460
Lat-strapply(x, (.*):(.*):(.*), Convert, simplify = TRUE)
Lat
#as you can see in Lat there are lots of 0's, which should not be there
but are because 'sign(dd)' takes +ve when +ve, -ve when -ve and
multiplies it by 'abs(dd)' which is correct, BUT for 0 it assigns
niether +ve or -ve, giving 0 a 0, and anything times 0 is 0..
#I modified the code to
latitude-as.vector(MD_LATITUD)
x - c(latitude)
Convert - function(d, m, s, dd = as.numeric(d), mm = as.numeric(m), ss
= as.numeric(s)) sign(ifelse(dd==0,sign(dd))) * (abs(dd) + mm / 60 + ss
/ 3600)
Lat-strapply(x, (.*):(.*):(.*), Convert, simplify = TRUE)
Lat
#so I now have the correct absolute decimal degrees in all cases and the
correct direction in all cases except where there should be a -0!,
because -0's are ignored and assumed to be the same as +0 which is wrong
because the + and - indicate direction.
# Do you know of a way I can get R to separate out the sign from
MD_LATITUD, so that I can change
# 'Convert - function(d, m, s, dd = as.numeric(d), mm = as.numeric(m),
ss = as.numeric(s)) sign(dd) * (abs(dd) + mm / 60 + ss / 3600)' to
something like
# 'Convert - function(sign, d, m, s, dd = as.numeric(d), mm =
as.numeric(m), ss = as.numeric(s)) sign * (abs(dd) + mm / 60 + ss /
3600) #(this does not work but something similar, or a different
approach may?)
Any help will be appreciated.
Thank you
sadz
From: David Winsemius dwinsem...@comcast.net
To: David Winsemius dwinsem...@comcast.net
Cc: Sadz A sadz_a1...@yahoo.co.uk; r-help@r-project.org
Sent: Wed, 20 October, 2010 20:45:39
Subject: Re: [R] Changing sign on absolute numbers 0 problems
On Oct 20, 2010, at 3:19 PM, David Winsemius wrote:
On Oct 20, 2010, at 11:47 AM, Sadz A wrote:
Hi,
I am trying to do some calculations turning DMS data to decimal
degrees using
the formula (D+(M/60)+(S/3600)), some of the D's involve -ve
numbers, the
easiest way to do the calculation
[R] Changing sign on absolute numbers 0 problems
Hi, I am trying to do some calculations turning DMS data to decimal degrees using the formula (D+(M/60)+(S/3600)), some of the D's involve -ve numbers, the easiest way to do the calculation is to use absolute numbers then use the 'sign' function in R to change the answer back to the correct -ve or +ve, for example, if; D--69 M-8 S-10 then decimal-D+(M/60)+(S/3600) -69+(8/60)+(10/3600) = this would equal -68.86389 (which is wrong, it should be -69.13611, so i used the following function) decimal-(abs(D)+(M/60)+(S/3600)) decimal.degs-sign(D)*decimal decimal.degs -69.13611 because ((69+(8/60)+(10/3600)=69.13611) and then the -sign is put back in. This works fine untill D=0 because then 'sign' does not give 0 a +ve sign it takes it as 0 and multiplies decimal by 0 to give 0. example D-0 decimal-D+(M/60)+(S/3600) decimal.degs-sign(D)*decimal decimal.degs 0 Is there anyway to get around this?? and make D=0 a positive and not a 0 with sign or another function?? Any help is appreciated Thank you sadz ps please email me if you need more info [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Changing sign on absolute numbers 0 problems
On Oct 20, 2010, at 11:47 AM, Sadz A wrote:
Hi,
I am trying to do some calculations turning DMS data to decimal
degrees using
the formula (D+(M/60)+(S/3600)), some of the D's involve -ve
numbers, the
easiest way to do the calculation is to use absolute numbers then
use the 'sign'
function in R to change the answer back to the correct -ve or +ve,
for example, if;
D--69
M-8
S-10
then
decimal-D+(M/60)+(S/3600)
-69+(8/60)+(10/3600) = this would equal -68.86389 (which is
wrong, it should
be -69.13611, so i used the following function)
decimal-(abs(D)+(M/60)+(S/3600))
decimal.degs-sign(D)*decimal
decimal.degs
-69.13611
because ((69+(8/60)+(10/3600)=69.13611) and then the -sign is put
back in.
This works fine untill D=0
because then 'sign' does not give 0 a +ve sign it takes it as 0 and
multiplies
decimal by 0 to give 0.
example
D-0
decimal-D+(M/60)+(S/3600)
decimal.degs-sign(D)*decimal
decimal.degs
0
Is there anyway to get around this??
I am not sure I understand the source of your distress. Why are you
disturbed that 0 returns 0? ??
and make D=0 a positive and not a 0 with sign or another
function??
You can always define your own function:
nonneg - function(x) { 0 + !sign(x) }
nonneg(0)
[1] 1
Any help is appreciated
Thank you
sadz
ps please email me if you need more info
--
David Winsemius, MD
West Hartford, CT
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Changing sign on absolute numbers 0 problems
Sadz A sadz_a1000 at yahoo.co.uk writes: This works fine untill D=0 because then 'sign' does not give 0 a +ve sign it takes it as 0 and multiplies decimal by 0 to give 0. example D-0 decimal-D+(M/60)+(S/3600) decimal.degs-sign(D)*decimal decimal.degs 0 decimal.degs - ifelse(D==0,1,sign(D))*decimal work? __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Changing sign on absolute numbers 0 problems
On Oct 20, 2010, at 3:19 PM, David Winsemius wrote:
On Oct 20, 2010, at 11:47 AM, Sadz A wrote:
Hi,
I am trying to do some calculations turning DMS data to decimal
degrees using
the formula (D+(M/60)+(S/3600)), some of the D's involve -ve
numbers, the
easiest way to do the calculation is to use absolute numbers then
use the 'sign'
function in R to change the answer back to the correct -ve or +ve,
for example, if;
D--69
M-8
S-10
then
decimal-D+(M/60)+(S/3600)
-69+(8/60)+(10/3600) = this would equal -68.86389 (which is
wrong, it should
be -69.13611, so i used the following function)
decimal-(abs(D)+(M/60)+(S/3600))
decimal.degs-sign(D)*decimal
decimal.degs
-69.13611
because ((69+(8/60)+(10/3600)=69.13611) and then the -sign is put
back in.
This works fine untill D=0
because then 'sign' does not give 0 a +ve sign it takes it as 0 and
multiplies
decimal by 0 to give 0.
example
D-0
decimal-D+(M/60)+(S/3600)
decimal.degs-sign(D)*decimal
decimal.degs
0
Is there anyway to get around this??
I am not sure I understand the source of your distress. Why are you
disturbed that 0 returns 0? ??
and make D=0 a positive and not a 0 with sign or another
function??
You can always define your own function:
nonneg - function(x) { 0 + !sign(x) }
nonneg(0)
[1] 1
Insufficient testing. Try instead:
nonneg - function(x) { 0+(x = 0 )}
nonneg(c(-2,-1,0,1,2))
[1] 0 0 1 1 1
Any help is appreciated
Thank you
sadz
ps please email me if you need more info
--
David Winsemius, MD
West Hartford, CT
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
West Hartford, CT
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Changing sign on absolute numbers 0 problems
On 10/20/2010 12:25 PM, Ben Bolker wrote: Sadz Asadz_a1000at yahoo.co.uk writes: This works fine untill D=0 because then 'sign' does not give 0 a +ve sign it takes it as 0 and multiplies decimal by 0 to give 0. example D-0 decimal-D+(M/60)+(S/3600) decimal.degs-sign(D)*decimal decimal.degs 0 decimal.degs- ifelse(D==0,1,sign(D))*decimal work? While Ben gives you what you asked for, I can see a pitfall that what you asked for is not what you really want. In that notation, there is a difference between 0 degrees and -0 degrees. However, as numbers, R would treat them as the same. identical(0L,-0L) [1] TRUE identical(0,-0) [1] TRUE So that information gets lost. Which really is another way of looking at the original question: when degrees are 0, the sign indicating east/west gets lost. The real solution involves going back to the original (string?) form of D, and separating out the sign and the number as two different pieces of information. -- Brian S. Diggs, PhD Senior Research Associate, Department of Surgery Oregon Health Science University __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
