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CORRECTION Re: [ferret_users] Gap in curvilinear fill plot



Hello Again,
A correction from my last e-mail. I found it necessary to define a modulo axes on the original grid before one regrids to the extra point in either x or y. Here is what I did to get the curvilinear fill command to look right:

def axis/x=1:20:1 xax
def axis/y=1:72:1/modulo yax !old modulo y-axis
def grid/x=xax/y=yax g1
file/grid=g1/var="lat,lon,u,v" file_name
def axis/y=1:73:1 nyax !new y-axis with extra point
def grid/like=g1/y=nyax g2
let nlat = lat[g=g2];let nlon = lon[g=g2];etc... !regridding
let speed = (nu^2 + nv^2)^0.5
fill speed,nlon,nlat

Hope this may help clarify things for other users.

Steve

Quoting guimond@coaps.fsu.edu:

Hello Muyin:
Thank you for your response. After some tooling around, I got what I was looking for. Originally, I tried adding the /modulo qualifier to my yaxis in order to span the gap in my plot, but the image I got was not pieced together properly (see attached "modulo.gif"). So taking your suggestion, I added a point in the yaxis and then regridded my lat,lons and variable to this new grid and got what I wanted (see attached "correct.gif"). I would have thought that adding /modulo and regridding to a grid with an extra point in y would have done the same thing, but it turns out the /modulo doesn't fit right.

Thanks again for your suggestion!

Steve


Quoting Muyin Wang <Muyin.Wang@noaa.gov>:

Hi, Stephen:
I found this problem when I plot NCEP's reanalysis data. The problem is due to the grid of the data. For NCEP's data, the grid is 0-360 along the longitude, with 144 points. Since the grid box is defined by the middle of the point, then there was a gap between 357.5 and 360 when I use polar-projection in my plot. A easy way to fix this is define another grid with ending point being 362.5, and regrid the data to the new grid. You are not changing anything, but add an extra point at the end to have an overlapping grid.
Good luck!
Muyin

Stephen R. Guimond wrote:

Hello,
I used the 3 arguement (curvilinear) fill command like so:

fill speed,lon,lat where speed,lon and lat are all two-dimensional arrays. The corresponding plot produces a gap in the data (see attached image "fill_curvilinear.gif"). To check on this, I used the go polymark/polygon command to plot scattered data and found that no gap exists in the data (see attached image "polymark.gif"). Any idea why the curvilinear version of fill is giving me this gap on my image? Also, just wondering if anyone has seen my last e-mail entitled "Plotting wind data on cylindrical grid" ??

Thanks Much,

Steve

=======================================================
Stephen R. Guimond
Graduate Research Assistant
Center for Ocean-Atmospheric Prediction Studies (COAPS)
Tallahassee, FL 32304
=======================================================

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=======================================================
Stephen R. Guimond
Graduate Research Assistant
Center for Ocean-Atmospheric Prediction Studies (COAPS)
Tallahassee, FL 32304
=======================================================

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