Hi Steve,
Thanks for the example where the /MODULO qualifier behaves this way.
This is a difficult problem, and there may not be any single solution
for all kinds of curvilinear grids. When you use the /MODULO
qualifier, Ferret adds and/or subtracts multiples of 360 to the
longitude coordinates. It's a shortcut for something you could do
yourself:
shade var, long, lati
shade/over var, long+360, lati
and so on, if more modulo replications are needed.
Ansley
guimond@coaps.fsu.edu wrote:
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
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Stephen R. Guimond
Graduate Research Assistant
Center for Ocean-Atmospheric Prediction Studies (COAPS)
Tallahassee, FL 32304
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