Re: curvilinear datasets

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi Julien,
The appearance of data in curvilinear data sets can be od, depending
on the grid. I haven't seen what you describe, but curvilinear data is 
fairly
new to me and I haven't seen a wide range of examples.

The regridding functions would let you put your data on a rectangular
grid and then you can do Ferret operations such as filling or smoothing.

One thing you can do to explore the data and the grid is to do plots
of the data and coordinates separately.

yes? SHADE rain[L=1]
yes? SHADE longicrs
yes? SHADE latitcrs

Sometimes visualizing the coordinates will help to understand
more about the grid.

Ansley


Julien Demaria wrote:

> Hi,
>
> I use this curvilinear netCDF dataset :
>
> netcdf out {
> dimensions:
>         time = 97 ;
>         i_cross = 39 ;
>         j_cross = 30 ;
>         pressure = 22 ;
> variables:
>         float time(time) ;
>                 time:units = "minutes since 2005-01-11 00:00:00" ;
>                 time:long_name = "time" ;
>         float latitcrs(i_cross, j_cross) ;
>                 latitcrs:units = "degrees" ;
>                 latitcrs:long_name = "LATITUDE (SOUTH NEGATIVE)" ;
>         float longicrs(i_cross, j_cross) ;
>                 longicrs:units = "degrees" ;
>                 longicrs:long_name = "LONGITUDE (WEST NEGATIVE)" ;
>         float rain(time, i_cross, j_cross) ;
>                 rain:units = "cm" ;
>                 rain:long_name = "ACCUMULATED NONCONVECTIVE 
> PRECIPITATION" ;
>         float vnorm(time, i_cross, j_cross) ;
>                 vnorm:units = "m s{-1}" ;
>                 vnorm:long_name = "10-meter Speed Norm" ;
>         float tau(time, i_cross, j_cross) ;
>                 tau:units = "-" ;
>                 tau:long_name = "Optical Thickness" ;
> }
>
> and when I shade or fill it (fill/L=2 vnorm, longicrs, latitcrs), I 
> have tholes on borders.
>
> With my little knowledges about Ferret, I understand that I have to 
> regrid my dataset on a regular grid to solve this problem ?
> For do this I need the new features "CURV_TO_RECT_MAP" and other 
> functions of Ferret 5.8, isn't it ?
>
> Are there some other solutions to my problem ?
>
> Other little problem : I try to download the new 5.8 release, but the 
> FTP always says "Control connection closed" ; are there some tricks 
> about FTP access (I believe I've successfuly downloaded the 5.7 
> release on this FTP in 2004 year, maybe you have made some recent 
> changes on your FTP...) ? Can I use a mirror ?
>
>
> Many Thanks in advance,
>
> Julien