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Lionel Roubeyrie wrote:
> By grd file, I mean csv like file, with one line by value, like
> X1	Y1	Z1
> X2	Y1	Z2
> X3	Y1	Z3
> ...
> X1	Y2	Zk
> X2	Y2	Zk+1
> ...
> Xi	Yj	Zn
> this is in geographic format, where there is a repetition in the X values and 
> the Y values, because the grid is regular, but not in lambert projection, 
> then I can't retrieve the dimensions of the grid.
>
> [SNIP]
Lionel: Well, I guess you are stuck without knowing what the dimensions 
of the grid are. Can't you find that out from the data provider?
-Jeff
-- 
Jeffrey S. Whitaker Phone : (303)497-6313
Meteorologist FAX : (303)497-6449
NOAA/OAR/PSD R/PSD1 Email : Jef...@no...
325 Broadway Office : Skaggs Research Cntr 1D-124
Boulder, CO, USA 80303-3328 Web : http://tinyurl.com/5telg

By grd file, I mean csv like file, with one line by value, like
X1	Y1	Z1
X2	Y1	Z2
X3	Y1	Z3
=2E..
X1	Y2	Zk
X2	Y2	Zk+1
=2E..
Xi	Yj	Zn
this is in geographic format, where there is a repetition in the X values a=
nd=20
the Y values, because the grid is regular, but not in lambert projection,=20
then I can't retrieve the dimensions of the grid.
Le Vendredi 20 Avril 2007 14:54, Jeff Whitaker a =E9crit=A0:
> Lionel Roubeyrie wrote:
> > Hi Jeff,
> > yes, lambert is not the problem, you're right. I have some .grd files
> > with x,y,z values, and I want to project z values on maps and interpola=
te
> > them. I don't have the dimensions of the shape, but with m.scatter(x, y,
> > z), I see that the scatters are displayed in a regular grid. Then is
> > there a way to retrieve the dimensions of the resulting grid, and then I
> > can reshape z to pass it to contourf?
>
> Lionel: There should be an attribute or attributes in the netCDF file
> that specify the dimensions of the grid (at least there should be,
> according to the GMT documentation).
>
> > I tried to convert x and y to degrees, hoping removing the duplicated
> > entries (with rouding) gives me the dimensions, but I also have a probl=
em
> > with m(x,y,inverse=3DTrue), because the results are not good ( I use m =
=3D
> > Basemap(llcrnrlon=3D0.5, llcrnrlat=3D44.8, urcrnrlon=3D2.8, urcrnrlat=
=3D46.5,
> > projection=3D'lcc', lat_1=3D45.89891889,lat_2=3D47.69601444,lon_0=3D2.3=
3722917)).
> > thanks
>
> You shouldn't need to do that - just pass x,y and the reshaped z to
> contourf. You do need to know the parameters of the projection though.
>
> -Jeff
=2D-=20
Lionel Roubeyrie - lro...@li...
Chag=E9 d'=E9tudes et de maintenance
LIMAIR - la Surveillance de l'Air en Limousin
http://www.limair.asso.fr

Lionel Roubeyrie wrote:
> Hi Jeff,
> yes, lambert is not the problem, you're right. I have some .grd files with 
> x,y,z values, and I want to project z values on maps and interpolate them. I 
> don't have the dimensions of the shape, but with m.scatter(x, y, z), I see 
> that the scatters are displayed in a regular grid. Then is there a way to 
> retrieve the dimensions of the resulting grid, and then I can reshape z to 
> pass it to contourf? 
> I tried to convert x and y to degrees, hoping removing the duplicated entries 
> (with rouding) gives me the dimensions, but I also have a problem with 
> m(x,y,inverse=True), because the results are not good ( I use m = 
> Basemap(llcrnrlon=0.5, llcrnrlat=44.8, urcrnrlon=2.8, urcrnrlat=46.5, 
> projection='lcc', lat_1=45.89891889,lat_2=47.69601444,lon_0=2.33722917)).
> thanks
Lionel: Basemap assumes that x=0,y=0 is the lower left corner of the 
projection region. You may have to adjust the x,y values coming from 
your grd file accordingly.
-Jeff
-- 
Jeffrey S. Whitaker Phone : (303)497-6313
NOAA/OAR/CDC R/PSD1 FAX : (303)497-6449
325 Broadway Boulder, CO, USA 80305-3328

Lionel Roubeyrie wrote:
> Hi Jeff,
> yes, lambert is not the problem, you're right. I have some .grd files with 
> x,y,z values, and I want to project z values on maps and interpolate them. I 
> don't have the dimensions of the shape, but with m.scatter(x, y, z), I see 
> that the scatters are displayed in a regular grid. Then is there a way to 
> retrieve the dimensions of the resulting grid, and then I can reshape z to 
> pass it to contourf? 
> 
Lionel: There should be an attribute or attributes in the netCDF file 
that specify the dimensions of the grid (at least there should be, 
according to the GMT documentation).
> I tried to convert x and y to degrees, hoping removing the duplicated entries 
> (with rouding) gives me the dimensions, but I also have a problem with 
> m(x,y,inverse=True), because the results are not good ( I use m = 
> Basemap(llcrnrlon=0.5, llcrnrlat=44.8, urcrnrlon=2.8, urcrnrlat=46.5, 
> projection='lcc', lat_1=45.89891889,lat_2=47.69601444,lon_0=2.33722917)).
> thanks
> 
You shouldn't need to do that - just pass x,y and the reshaped z to 
contourf. You do need to know the parameters of the projection though. 
-Jeff
-- 
Jeffrey S. Whitaker Phone : (303)497-6313
NOAA/OAR/CDC R/PSD1 FAX : (303)497-6449
325 Broadway Boulder, CO, USA 80305-3328

Hi Jeff,
yes, lambert is not the problem, you're right. I have some .grd files with=
=20
x,y,z values, and I want to project z values on maps and interpolate them. =
I=20
don't have the dimensions of the shape, but with m.scatter(x, y, z), I see=
=20
that the scatters are displayed in a regular grid. Then is there a way to=20
retrieve the dimensions of the resulting grid, and then I can reshape z to=
=20
pass it to contourf?=20
I tried to convert x and y to degrees, hoping removing the duplicated entri=
es=20
(with rouding) gives me the dimensions, but I also have a problem with=20
m(x,y,inverse=3DTrue), because the results are not good ( I use m =3D=20
Basemap(llcrnrlon=3D0.5, llcrnrlat=3D44.8, urcrnrlon=3D2.8, urcrnrlat=3D46.=
5,=20
projection=3D'lcc', lat_1=3D45.89891889,lat_2=3D47.69601444,lon_0=3D2.33722=
917)).
thanks
Le Vendredi 20 Avril 2007 13:11, Jeff Whitaker a =E9crit=A0:
> Lionel Roubeyrie wrote:
> > hi all,
> > is there a way to plot (contourf) a .grd file from GMT directly with
> > Basemap? I have a problem with contourf because I can't reshape to 2D t=
he
> > Z values ,x and y are in Lambert projection, so I can't compute the sha=
pe
> > :-( thanks
>
> Lionel: No, not directly. You have to read in the x,y,z values and
> convert them to 2D arrays. You'll have to give more details on your
> problem - just because x,y are in Lambert projection coordinates doesn't
> mean you can't reshape z.
>
> -Jeff
=2D-=20
Lionel Roubeyrie - lro...@li...
Chag=E9 d'=E9tudes et de maintenance
LIMAIR - la Surveillance de l'Air en Limousin
http://www.limair.asso.fr

Lionel Roubeyrie wrote:
> hi all,
> is there a way to plot (contourf) a .grd file from GMT directly with Basemap? 
> I have a problem with contourf because I can't reshape to 2D the Z values ,x 
> and y are in Lambert projection, so I can't compute the shape :-(
> thanks
>
> 
Lionel: No, not directly. You have to read in the x,y,z values and 
convert them to 2D arrays. You'll have to give more details on your 
problem - just because x,y are in Lambert projection coordinates doesn't 
mean you can't reshape z. 
-Jeff
-- 
Jeffrey S. Whitaker Phone : (303)497-6313
NOAA/OAR/CDC R/PSD1 FAX : (303)497-6449
325 Broadway Boulder, CO, USA 80305-3328

hi all,
is there a way to plot (contourf) a .grd file from GMT directly with Basema=
p?=20
I have a problem with contourf because I can't reshape to 2D the Z values ,=
x=20
and y are in Lambert projection, so I can't compute the shape :-(
thanks
=2D-=20
Lionel Roubeyrie - lro...@li...
Chag=C3=A9 d'=C3=A9tudes et de maintenance
LIMAIR - la Surveillance de l'Air en Limousin
http://www.limair.asso.fr