Re: Dimensions and Variables

• To: mathgroup at smc.vnet.net
• Subject: [mg13728] Re: Dimensions and Variables
• From: Paul Abbott <paul at physics.uwa.edu.au>
• Date: Wed, 19 Aug 1998 01:38:20 -0400
• Organization: University of Western Australia
• References: <6r102b\$fi7@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Naum Phleger wrote:

> 1)Why does Dimensions comand return 2 for x*Cos[y]?  I need to check
> dimensions of quantities and this makes it dificult to do.

The Dimensions function in Mathematica yields the structure of
expressions, e.g., for a matrix,

In[1]:= Dimensions[{{a, b}, {c, d}}] Out[1]= {2, 2}

You may find that the Miscellaneous`Units` package (which comes with
Mathematica) is relevant to what you are after.

> 3)Does Mathematica Know anything about map projections.  I have a vector
> feild of the sky and I want to plot it in a certin projection.  All I
> have been able to do so far is plot vectors on square euclidian space.

Have a look at Miscellaneous`WorldPlot` (and also Graphics`ComplexMap`).

Cheers,
Paul

____________________________________________________________________
Paul Abbott                                   Phone: +61-8-9380-2734
Department of Physics                           Fax: +61-8-9380-1014
The University of Western Australia            Nedlands WA  6907
mailto:paul at physics.uwa.edu.au  AUSTRALIA
http://www.physics.uwa.edu.au/~paul

God IS a weakly left-handed dice player
____________________________________________________________________

```

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