[Tutor] Request for advice on Python code

[Mark Lawrence]

On 13/02/2012 23:50, Elaina Ann Hyde wrote:
> Hi, I'm working on a routine for reading in the Schlegel dustmaps.  I have
> an ascii table with values, Ra-Dec and I'm trying to convert 2 columns to
> l,b and get the dust values out, this is a 2 part problem as I need to
> first convert to l,b, keep those values for other uses (calculating VLSR),
> and get extinctions for each l,b value, I have:
>
> import astropysics
> from astropysics.coords import ICRSCoordinates,GalacticCoordinates
> import asciitable
>
> x='Core_rod_name.list'
> dat=asciitable.read(x,Reader=asciitable.CommentedHeader,
> fill_values=['','-999.99'])
> Radeg=dat['ra-drad']*180./math.pi
> Decdeg=dat['dec-drad']*180./math.pi
>
> plot(Radeg,Decdeg,'o')
> xlabel('Radeg')
> ylabel('Decdeg')
>
> gcoords=ICRSCoordinates(dat['ra-drad'],dat['dec-drad'],radians=True).convert(GalacticCoordinates)
> l=gcoords.l.degrees
> b=gcoords.b.degrees
>
> VLSR=dat['Vhel_f'] + 9*np.cos(l)*np.cos(b) + 12*np.sin(l)*np.cos(b) +
> 7*np.sin(b)
> VGSR=VLSR + 220*np.sin(l)*np.cos(b)
>
> dustmap='SFD_dust_4096_ngp.fits'
> EB_V=astropysics.obstools.get_SFD_dust(l,b,dustmap,interpolate=True)
> -------
> this gives the error 'Only length-1 arrays can be converted to Python
> scalars' ... however, I cannot do:
>
> for row in dat:
>
> gcoords=ICRSCoordinates(dat['ra-drad'],dat['dec-drad'],radians=True).convert(GalacticCoordinates)
>
> without the same error.  Any ideas would be apreciated, thanks!
>
> ~Elaina
>
>
>
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Well it's as clear as dust to me :)

Unlike others who have already responded I don't believe that this will 
be too difficult to sort as the astropysics package is available on Pypi 
and there it states that it requires scipy and numpy.  Did you or 
someone else install the package, if the latter can you ask them about 
this problem?

Best of British/Australian/Whatever luck with this.

-- 
Cheers.

Mark Lawrence.