Your suggestion worked like a charm. Thank you
rle <- rle(TF$Speed)$lengths #Counts number of repetitions
phdf$rle <- rep(rle>9,rle) #TRUE is ten or more zeros. FALSE if less than 10
phdf2 <- TF[rep(rle<10,rle),] #Move rows that are FALSE to new data file
From: Bert Gunter
Sent: Friday, August 14, 2020 2:43 PM
To: Philip
Cc: r-help
Subject: Re: [R] Hot Air Balloon Weather Briefings
Well which is it?:
"I want to eliminate the data for minute 30 but keep the data for minute 31
because the balloon starts to move again at second 17. "
or
"It would be even better if I could delete the rows where there were ten
consecutive zero speed entries such as from minute 30 second 17 to minute 31
second 11."
If you want to delete say data with >= 10 consecutive 0's, ?rle is your friend:
rle(phdf$Speed)
Run Length Encoding
lengths: int [1:10] 15 1 1 1 1 1 1 1 1 1
values : num [1:10] 0 0.402649 0.671081 1.588225 2.438261 2.706693 2.930386
3.310666 3.198819 3.422512
e.g.
> z <- rle(phdf$Speed)$lengths
## which gives:
> z
[1] 15 1 1 1 1 1 1 1 1 1
> rep(z>9,z)
[1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
[11] TRUE TRUE TRUE TRUE TRUE FALSE FALSE FALSE FALSE FALSE
[21] FALSE FALSE FALSE FALSE
##Thus:
> phdf[ rep(z<10, z), ]
Minute Second Speed
16 31 17 0.402649
17 31 23 0.671081
18 31 29 1.588225
19 31 35 2.438261
20 31 41 2.706693
21 31 47 2.930386
22 31 53 3.310666
23 31 59 3.198819
24 32 5 3.422512
But of course, this probably isn't what you meant. So further clarification is
needed.
Bert Gunter
"The trouble with having an open mind is that people keep coming along and
sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
On Fri, Aug 14, 2020 at 1:59 PM Philip <herd_...@cox.net> wrote:
I’m trying to compare National Weather Service Rapid Update Forecast (RAP)
data to GPS breadcrumbs collected by a really clever Apple Phone Ap that lays
down longitude, latitude, altitude, compass direction, and speed every six
seconds. Below is a small subset of the GPS data from another flight.
I want to delete the rows where the balloon does not move (Speed column) for
a full minute assuming that it is sitting on the ground – beginning of the
flight, changing passengers, or waiting for the chase crew at the end of the
flight. for example, I want to eliminate the data for minute 30 but keep the
data for minute 31 because the balloon starts to move again at second 17. Any
suggestions? I’ve tried putzing around with multiple lags without success.
Minute Second Speed
29 47 0
29 53 0
29 59 0
30 5 0
30 11 0
30 17 0
30 23 0
30 29 0
30 35 0
30 41 0
30 47 0
30 53 0
30 59 0
31 5 0
31 11 0
31 17 0.402649
31 23 0.671081
31 29 1.588225
31 35 2.438261
31 41 2.706693
31 47 2.930386
31 53 3.310666
31 59 3.198819
32 5 3.422512
It would be even better if I could delete the rows where there were ten
consecutive zero speed entries such as from minute 30 second 17 to minute 31
second 11.
Thanks,
Philip Heinrich
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