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[IDV #TYB-719779]: Support request

Hi Mohit-

> Don, one question...
> Is it possible to use two different grid files such as wind speed at 850mb
> and surface temperature (ground level) for multiplying together using IDV ?

You should use the mul(s1,s2) Jython method to do the multiplication
which should handle special cases (e.g. 2D grid X slice of 3D grid).

Don
P.S. I will have limited e-mail contact shortly for the next week,
so if you have other questions on this regard, they may not get answered
right away.



> address@hidden> wrote:
> 
> > Hi Mohit-
> >
> > > I used the formula, dirn(vecr(u,v)) for producing wind azimuth map. I'm
> > not
> > > able to figure out whether the code "(dirn(vecr(u,v))" takes north or
> > east
> > > into account for calculating the direction of wind. I would request you
> > to
> > > give me some hints for solving this issue.
> >
> > Yes it does.  dirn gives the direction relative to true north, dirr gives
> > the direction in grid relative coordinates.  See the documentation at:
> >
> >
> > http://www.unidata.ucar.edu/software/IDV/docs/userguide/tools/JythonLib.html
> >
> > > Thanks for the guidance. Now, i am able to produce wind angle grid using
> > U
> > > and V wind component but the value ranges from 0 to 255 degree. I will be
> > > thankful, if you could explain me about fixing up the exact wind angle
> > > values.
> >
> >
> > What display are you using to view these?  If you are using the image
> > display, then the default range for the color table is 0 to 255.  You
> > can change this by using the Change Range menu in the Color Table menu
> > of the display control.  Change it to 0 to 360.
> >
> > Don Murray
> >
> > > On Thu, Nov 20, 2008 at 1:20 AM, Mohit Kalra <address@hidden> wrote:
> > >
> > > > Hi Don,
> > > >
> > > > Thanks for the guidance. Now, i am able to produce wind angle grid
> > using U
> > > > and V wind component but the value ranges from 0 to 255 degree. I will
> > be
> > > > thankful, if you could explain me about fixing up the exact wind angle
> > > > values.
> > > >
> > > > Thanks in advance.
> > > >
> > > > Mohit
> > > >
> > > >
> > > >
> > > >
> > > > address@hidden> wrote:
> > > >
> > > >> Hi Mohit-
> > > >>
> > > >> > I guess, produced wind vector flow is not in the form of grid. I
> > tried
> > > >> to
> > > >> > use dirn(Vector) formula using driv jython method. In the formula
> > editor
> > > >> > used dirn(Vector) for calling the formula. I had impression that the
> > > >> > formula will convert wind flow vector into wind azimuth (angle)
> > grid.
> > > >> The
> > > >> > issue is need to assign wind flow vector as an input in the field
> > > >> selector
> > > >> > window. Unfortunetly, produced wind flow vector is not appearing
> > into
> > > >> the
> > > >> > field selctor window. I would request you to test the attached data
> > > >> > (previous mail) for producing the wind azimuth angle grid. I would
> > also
> > > >> > request you to kindly explain me the steps for the same.
> > > >>
> > > >> You can create the vector from the u and v using the vecr Jython
> > procedure
> > > >> or by using the "Grid->Make flow vectors from grid relative u and v
> > data"
> > > >> formula.
> > > >>
> > > >> You can use the Grid->Create Grid Diagnostic formula and in the
> > > >> dialog, use  dirn(vecr(u,v)).  You will then be prompted for the
> > > >> u and v variables and can select your u and v grids at that point.
> > > >> Or you could create a new formula to hold dirn(vecr(u,v)) so you can
> > > >> call it over and over.
> > > >>
> > > >> Don Murray
> > > >> > On Wed, Nov 19, 2008 at 8:10 PM, Mohit Kalra <address@hidden>
> > > >> wrote:
> > > >> >
> > > >> > > Dear Don,
> > > >> > >
> > > >> > > Thanks for your quick reply. Though, i'm using IDV but not
> > familiar
> > > >> with
> > > >> > > all the functions. So, i would be thankful, if you could explain
> > me
> > > >> steps
> > > >> > > for using dirn or dirv Jython methods in the griddiag.py. Further,
> > i
> > > >> > > enclosed wind data in netCDF format for your consideration (U and
> > V
> > > >> > > component at 850mb pressure level with geopotential height). I'm
> > > >> interested
> > > >> > > in producing the raster grid with the wind angle value from 0 to
> > 360
> > > >> degree.
> > > >> > >
> > > >> > >
> > > >> > > Waiting for your reply.
> > > >> > >
> > > >> > > Thanks and regards,
> > > >> > >
> > > >> > > Mohit
> > > >> > >
> > > >> > >
> > > >> > >
> > > >> > >
> > > >>
> > ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> > > >> > >
> > > >> > >
> > > >> > >
> > > >> > >
> > > >> > > address@hidden> wrote:
> > > >> > >
> > > >> > >> Hi Mohit-
> > > >> > >>
> > > >> > >> This is Don.
> > > >> > >>
> > > >> > >> > Thanks for your reply. I have another question regarding wind
> > > >> vector
> > > >> > >> flow
> > > >> > >> > estimation using IDV. I have calculated wind speed and flow
> > vector
> > > >> using
> > > >> > >> U,
> > > >> > >> > V and W component of wind. I am wondering if the flow vector
> > could
> > > >> be
> > > >> > >> use
> > > >> > >> > for getting the wind azimuth angle from 0 to 360 degree.
> > > >> > >> >
> > > >> > >> > Looking forward to hear from you.
> > > >> > >> >
> > > >> > >> > Thanks and regards,
> > > >> > >>
> > > >> > >> You can calculate the direction using the dirn or dirv Jython
> > > >> > >> methods in the griddiag.py.  dirn will return the true north
> > > >> > >> direction, dirv will return the grid relative direction (if
> > > >> > >> you have a grid relative vector).  You would call this with
> > > >> > >>
> > > >> > >> dirn(vector)
> > > >> > >>
> > > >> > >> where vector is the flow vector grid.
> > > >> > >>
> > > >> > >> Don Murray
> > > >> > >>
> > > >> > >> Ticket Details
> > > >> > >> ===================
> > > >> > >> Ticket ID: TYB-719779
> > > >> > >> Department: Support IDV
> > > >> > >> Priority: High
> > > >> > >> Status: Open
> > > >> > >>
> > > >> > >>
> > > >> > >
> > > >> >
> > > >> >
> > > >>
> > > >>
> > > >> Ticket Details
> > > >> ===================
> > > >> Ticket ID: TYB-719779
> > > >> Department: Support IDV
> > > >> Priority: High
> > > >> Status: Open
> > > >>
> > > >>
> > > >
> > >
> > >
> >
> >
> > Ticket Details
> > ===================
> > Ticket ID: TYB-719779
> > Department: Support IDV
> > Priority: High
> > Status: Open
> >
> >
> 
> 


Ticket Details
===================
Ticket ID: TYB-719779
Department: Support IDV
Priority: High
Status: Open