[Proj] Proj4 Projection Coordinates for Geostationary satellite data

[Kathryn Jablonski - NOAA Affiliate]

Thanks Janne.

We did try drawing a limiting box inside the earth extents to get all valid
data points within, and this works but cuts out data in the edges of the
earth.  See the following image:

[image: Inline image 1]
We still need the data in between the drawn dotted line blue box and the
edge of the earth.  The data values in the red shaded off earth areas are
very large (2.14 E9) and these are the values that throw the error.  If you
do discard the values in the light red, that is fine but it is throwing an
exception instead, preventing us from proceeding forward.

Thanks for the support!



On Tue, Aug 13, 2013 at 3:12 AM, <support.mn at elisanet.fi> wrote:

> Hello,
>
> we just discarded all points outside any reasonable area.
> Another possibility might be to draw a limiting line (or box)
> and move all outside points to that..
>
> Hope that helps?
>
> Regards: Janne.
>
>
> ----------------------------------------------------------------------------------------
>
> Kathryn Jablonski - NOAA Affiliate [kathryn.jablonski at noaa.gov] kirjoitti:
> > I am trying to convert geographic coordinates (in degrees east/north lat
> > lon) to projected coordinates in meters for geostationary full disc data
> > (GVAR Goes East data from CLASS).  To do this, I tried using PyProj/
> Proj4
> > and am running into errors due to the off earth pixels in the corners.
> >
> > This is the proj4 string given:
> >  projection_coords = Proj("+proj=geos +h=35774290 +a= 6378137 +b= 6378137
> > +lon_0=-75 +units=meters +no_defs")
> > ll_x, ll_y = projection_coords_geos( LL_y_deg, LL_x_deg, inverse = False,
> > errcheck=True)
> >     'x=%9.3f y=%11.3f' % (ll_x,ll_y)
> >     ur_x,ur_y = projection_coords_geos( UR_y_deg, UR_x_deg, inverse =
> > False, errcheck=True)
> >  'x=%9.3f y=%11.3f' % (ur_x,ur_y)
> >
> > For full disc geos data I am receiving incorrect (1e30) values for the
> > extents and was wondering if anyone has ever run into the same error or
> > have a suggestion to correct this.
> >
> > Also, for remapping GOES data, should the 'sweep axis' be including in
> the
> > Proj string and set to 'y'?
> >
> > Thanks in advance for any suggestions!
> >
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>
>
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