Mercator projection in Grads

[Suru Polade]

Dear

        Sir

               I have emission field from WRF-Chem model over the Indian
Region, at the resolution of 1/4 Deg,

         with

                 True Latitude 1 =   22.875

                 Center    Lat    =    22.875

                Center     LON  =    82.875

                 DX                  =    1/4 Deg



          North West  corner Lat Lon ( 36.79, 66.77)

          South West corner Lat Lon (7.33, 66.77)

          North East   Corner Lat Lon (36.79, 98.98)

          South East Corner  Lat Lon ( 7.38, 98.98)



if with 1/4 deg we are calculation number of Grid  it will come

       North South Grid number  117

       West East Grid number    129



but in WRF-SI, Dx we need to give in Km

if considering 1 Deg = 110 Km then dx will come 27.5 km

that will create 121 X 121 Grid with same center and corner lat lon for
Mercator projection



so if giving 121 X 121 in ctl file then emission field is shifting from it's
original lat lon position.



i am attaching here data file gs file and ctl file, can you please go
through it





 your sincerely



Suraj


On 11/13/07, Brian Doty <doty at cola.iges.org> wrote:
>
> A Mercator grid is typically rectangular in lat/lon, and can be dealt
> with using the "levels" keyword on the ydef statement in the
> descriptor file... Brian
>
> On Nov 13, 2007, at 5:43 AM, Suru Polade wrote:
>
> > I have a pre-projected field in a Mercator projection
> >
> >                     Is there any way in grads to work with Mercator
> > projection, as this projection is not there for pre-projected data.
> >
>
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