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Re: A question about a sphere

  • To: mathgroup at smc.vnet.net
  • Subject: [mg107057] Re: [mg107038] A question about a sphere
  • From: "David Park" <djmpark at comcast.net>
  • Date: Tue, 2 Feb 2010 03:24:12 -0500 (EST)
  • References: <24744797.1265023377774.JavaMail.root@n11>

Here is an easy solution using the Presentations package. First we
parametrize a sphere and then draw the sphere, the lines of latitude, and
the lines of longitude using the parametrization. (We could have just used
Sphere for the sphere.) I used 6 lines of longitude in honor of the
Babylonians. 

Needs["Presentations`Master`"] 

sphere[r_, \[Phi]_, \[Theta]_] := 
 r {Cos[\[Phi]] Cos[\[Theta]], Cos[\[Phi]] Sin[\[Theta]], Sin[\[Phi]]}  

Draw3DItems[
 {(* Draw the sphere *)
  Opacity[.5], Orange,
  ParametricDraw3D[
   sphere[1, \[Phi], \[Theta]], {\[Phi], -\[Pi]/2, \[Pi]/
     2}, {\[Theta], 0, 2 \[Pi]},
   Mesh -> None],
  (* Draw 5 lines of latitude *)
  Opacity[1], Black,
  Table[ParametricDraw3D[
    sphere[1, lat, \[Theta]], {\[Theta], 0, 
     2 \[Pi]}], {lat, {80 \[Degree], 40 \[Degree], 
     0, -40 \[Degree], -80 \[Degree]}}],
  (* Draw lines of longitude *)
  Table[ParametricDraw3D[
    sphere[1, \[Phi], long], {\[Phi], -\[Pi]/2, \[Pi]/2}], {long, 0, 
    300 \[Degree], 60 \[Degree]}]},
 NeutralLighting[0, .5, .1, 0 \[Degree], -30 \[Degree]],
 NiceRotation,
 Boxed -> False,
 ImageSize -> 400]  

NeutralLighting provides white lights with a little ambient light and
lowered to give a better rendering. NiceRotation prevents jumping of the
image if you rotate with the mouse.


David Park
djmpark at comcast.net
http://home.comcast.net/~djmpark/  


From: Marwa Abd El-Wahaab [mailto:m.a.elwahaab at gmail.com] 


Dear Sir,

I am a Mathematica 7 user.

I have a question :

I want to draw a sphere, then draw 5 circles on this sphere like
*latitudes*and draw 5 lines on this sphere like
*longitudes*.

I need your help.

Thanks in advance

Marwa Ali





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