Thank you mam for reply, I understood it in ferret since it has inbuild function which takes care about line segment but at the end you have used
GO stick_vectors plot ucomp, vcomp
How
function "stick_vectors" generates line segments, how it replaces actual U values in x axis with timestamp ?
My array would look something like this, if I take number say starts from 0 - 3, I actually want to replace it with time, otherwise x axis will be negative as it contains U component -3.969 to 3.593
stick1-> [0, 0],[-3.969 + 0,-1.001]
stick2-> [1, 0],[-4.578 + 1, 0.596]
stick3-> [2,
0],[1.593 + 2, 0.484]
stick4-> [3, 0],[-1.622 + 3, 1.580]
The same example in case of ferret
let u = {-3.969,-4.578,1.593,-1.622}
let v = {0.596,-1.001,0.484,1.580}
plot/set/vlim=-2:2:0.1/hlim=-4:4:0.5/vgrat=line/hgrat=line/color=red/thickness=2 u,v
ppl plotuv
Thanks for
reply
- Dona
On Tuesday, July 1,
2014 10:10 PM, Ansley Manke <ansley.b.manke@xxxxxxxx> wrote:
still, you'll need to know the units and origin of the time data,
then all of the times can be translated to dates and times inside
Ferret. Is 379987200000 expressed as milliseconds since the start
of some year? Or seconds since some time? 379987200000 is about
12 years' worth of milliseconds, so is this milliseconds since the
start of 1970? This is just a guess. I don't know for sure.
In Ferret, divide by number of days/year, hours/day, minutes/hour,
seconds/hour, milliseconds/second:
yes? list 379987200000 /(365.2425*24*3600*1000)
VARIABLE : 379987200000 /(365.2425*24*3600*1000)
12.04
The logic for the time definitions is to convert time coordinates
and time origin to calendar time. Maybe that's all you need for what
you're doing. I know that Java has time libraries that will handle
these kinds of conversions.
To proceed in Ferret, we would divide the input data by 1000 for
time units of seconds:
yes? file/var="t_in, zero,
u, v" my_data.dat
yes? define axis/t/units=seconds/t0="1-jan-1970"
timeax = t_in/1000
yes? list t[gt=timeax]yes? list t[gt=timeax]
VARIABLE : T
axis TIMEAX
SUBSET : 4 points (TIME)
16-JAN-1982 00 / 1: 3.800E+08
16-FEB-1982 00 / 2: 3.827E+08
16-MAR-1982 00 / 3: 3.851E+08
16-APR-1982 00 / 4: 3.878E+08
yes? let ucomp =
reshape(u,t[gt=timeax])
yes? let vcomp =
reshape(v,t[gt=timeax])
yes? GO stick_vectors plot ucomp, vcomp
On 6/30/2014 10:14 PM, Don DNA wrote:
Thank you so much
madom for your prompt reply, and sorry for not being clear,
actually I am developing application in my school using
java, for that I need to understand logic to calcuate
timeshift, I need to generate date something like this for
line segments
stick = > from [ date , 0 ] to [
newtimeshift_date, v-component ]
will be
stick
=> from [379987200000 , 0 ] to [ ? , 0.596 ]
and
379987200000 is actually Sat, 16 Jan 1982 00:00:00
I hope you
will understand my problem now
- Dona
Hi,
Have you been able to read your data into Ferret?
UTC simply means Coordinated Universal Time, but
what is the data unit? Seconds, maybe? and since
what time origin? Your data source should tell you
more than just "UTC".
Ferret will be able to convert those data to time
steps once one knows that. You would read in the
three variables, define a time axis using the first
one, and RESHAPE your u and v components to that
time axis. Fill in the right things in the DEFINE
AXIS command, and you should be set
.
yes?
file/var="tsec, zero, u, v" my_data.dat
yes? define axis/t/units=seconds/t0="???" timeax =
tsec
yes? let ucomp =
reshape(u,t[gt=timeax])
yes? let vcomp =
reshape(v,t[gt=timeax])
It would be a good idea to add /UNITS= on the LET
commands to give the velocity components their
correct units. Then you should be able to try the
stick_vectors script to make a plot.
Ansley
On 6/30/2014 5:42 AM, 'Don
DNA' via _OAR PMEL Ferret Users wrote:
I
read answer from ferret userlist
regarding stick plot from here, and I
don't have much knowledge about
ferret, even to read source code
I have "UTC date, u -
component, v-component " I
am interested to calculate
time shift, can someone
please help me to calculate
time shift for line
segments,
My
data looks something like
this
UTC
data, Zero, U-comp,
V-component
379987200000,0,
-3.969,0.596
382665600000,0,
-4.578,-1.001
385084800000,0,1.593,0.484
387763200000,0, -1.622,1.58
Can
someone please explain me,
time shift for above input,
I actually did not
understand this "
from (c*t, 0) to (c*t+u(t), v(t))", if I
just add utc date to
U(t) - component I will
get very close value and
I will not get slope,
please help me..