Group Abstract Group Abstract

Message Boards Message Boards

1
|
2.1K Views
|
1 Reply
|
3 Total Likes
View groups...
Share
Share this post:

Full circle of earth meridian

Tom Wiesand
Posted 5 years ago

1) I cannot get the full circle with the spherical formula:

ParametricPlot3D[ CoordinateTransform["Spherical" -> "Cartesian", { 1, t, 0}], {t, 0, 2 Pi},AxesLabel->{x,y,z}]

produces the same half circle as:

ParametricPlot3D[ CoordinateTransform["Spherical" -> "Cartesian", { 1, t, 0}], {t, 0, Pi},AxesLabel->{x,y,z}]

2) Another problem is with the equator (why only half circle?) :

ParametricPlot3D[ CoordinateTransform["Spherical" -> "Cartesian", { 1, Pi/2, t}], {t, 0, 2 Pi}, AxesLabel->{x,y,z}]

But the following can draw the equator:

ParametricPlot3D[ CoordinateTransform["Spherical" -> "Cartesian", { 1, Pi/2, t}], {t, -Pi, Pi}, AxesLabel->{x,y,z}]
POSTED BY: Tom Wiesand
1 Reply
Sort By:

It is because CoordinateTransform["Spherical" -> "Cartesian", {1, t, 0}] refuses numerical values of t not between 0 and Pi. You can bypass that with Evaluate:

ParametricPlot3D[
 Evaluate@CoordinateTransform[
   "Spherical" -> "Cartesian", {1, t, 0}], {t, 0, 2 Pi}, 
 AxesLabel -> {x, y, z}]

so that the coordinate transformation will be computed symbolically before the numerical check kicks in. Similarly for longitudes:

ParametricPlot3D[
 CoordinateTransform[
  "Spherical" -> "Cartesian", {1, Pi/2, t}], {t, -Pi, Pi}, 
 AxesLabel -> {x, y, z}]
POSTED BY: Gianluca Gorni
Reply to this discussion
Community posts can be styled and formatted using the Markdown syntax.
Tag limit exceeded
Note: Only the first five people you tag will receive an email notification; the other tagged names will appear as links to their profiles.
Reply Preview
Attachments
Remove
or Discard