| How to plot the magnetic field vector along the trajectory [message #59133] |
Tue, 11 March 2008 20:05  |
duxiyu@gmail.com
Messages: 88
Registered: March 2007
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Member |
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Dear all,
I have the magnetic field data and spacecraft position data.
I want to plot the magnetic field vector along the trajectory.
I think I should first plot the spacecraft trajectory, and then plot
the magnetic field vector along the trajectory.
But I do not know which procedure in IDL can perform the second step.
Is there anyone who can can help me?
Best wishes,
Du
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| Re: How to plot the magnetic field vector along the trajectory [message #59256 is a reply to message #59133] |
Thu, 13 March 2008 06:33  |
mankoff
Messages: 131
Registered: March 2004
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Senior Member |
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On Mar 13, 8:40 am, "dux...@gmail.com" <dux...@gmail.com> wrote:
> I am not sure what the 'idldemo' means and cannot find its information
> in IDL Help.
> Could you introduce it in detail?
>
> Du
>
> On Mar 13, 1:00 am, mankoff <mank...@gmail.com> wrote:
>
>> On Mar 12, 11:09 am, Lasse Clausen <la...@lbnc.de> wrote:
>
>>> On 12 Mar, 15:45, David Fanning <n...@dfanning.com> wrote:
>
>>>> Lasse Clausen writes:
>>>> > We are not throwing away anything, we are merely projecting into the
>>>> > XY plane... ;-) You have to project somewhere as the computer screen
>>>> > is not capable of displaying 3D - nor is paper, incidentally. And the
>>>> > usual way to do this kind of thing is to provide three plots, one in
>>>> > the XY plane, one in XZ and one in YZ. You then have to assemble the
>>>> > 3D picture in your head.
>
>>>> Or, you could envision an object graphics solution with
>>>> an "earth" and "satellite" revolving around it, casting
>>>> a shadow trajectory onto the earth with a magnetic vector
>>>> rotating about in the plane of the satellite.
>
>>>> All I'm saying is, the question lacked enough detail,
>>>> for whatever good reason, to know how to form a sensible
>>>> answer. And that when you ask better questions, you get--
>>>> generally--better answers.
>
>>>> I agree that this question was borderline for such a
>>>> response. Even I could tell English was not the first
>>>> language. But coming, as it did, at the end of a long
>>>> day and after several seriously bad questions from the
>>>> past week, I just thought a reminder might be useful. :-)
>
>>>> Cheers,
>
>>>> David
>>>> --
>>>> David Fanning, Ph.D.
>>>> Fanning Software Consulting, Inc.
>>>> Coyote's Guide to IDL Programming:http://www.dfanning.com/
>>>> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
>
>>> As I said earlier, the question did not lack detail for me because I
>>> have seen lots of these kind of plots before, so I was pretty sure
>>> what was asked for. But I can also see that it would be confusing if I
>>> hadn't seen these plots before.
>
>>> More importantly, IDL can do that sort of thing? With shadows and all?
>>> Object graphics I hear you say... Mmmm, so far I have ignored
>>> everything involving object graphics. Well, maybe one fine day.
>
>>> Cheers
>>> Lasse Clausen
>
>> Play around with "idldemo". There is a satellite orbiting the earth (I
>> think with Ground Track). The earth is rotating. Clouds are rotating
>> separately from Earth, etc.
>
>
Type "idldemo" at the *nix CLI, or "demo" at the IDL> prompt in IDL to
see the demo.
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| Re: How to plot the magnetic field vector along the trajectory [message #59257 is a reply to message #59133] |
Thu, 13 March 2008 05:42 |
duxiyu@gmail.com
Messages: 88
Registered: March 2007
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Member |
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Thank you, Manodeep,
It is very useful for me.
Du
On Mar 13, 5:30 am, Manodeep Sinha <manod...@gmail.com> wrote:
> Hello Du,
>
> For a 2-d projection, try partvelvec.pro ( http://www.astro.washington.edu/deutsch-bin/getpro/library32 .html?PARTVELVEC)
>
> velovect needs your data to be in a 2-d array format instead of the
> scattered data points that you have.
>
> Alternatively, the plots solution with a previous call to scale3 to
> establish the axis and the
> ranges should also be sufficient.
>
> Cheers,
> Manodeep
>
> On Mar 12, 10:35 am, jdu <jdu.u...@gmail.com> wrote:
>
>> Thanks a lot.
>> I have found the internal procedure 'VELOVECT' which can produces a
>> two-dimensional velocity field plot.
>> It just meet my request.
>> It seems that the 'iVector' can also produce the figures I want.
>
>> Du
>
>> On Mar 12, 10:23 pm, Lasse Clausen <la...@lbnc.de> wrote:
>
>>> On 12 Mar, 14:26, David Fanning <n...@dfanning.com> wrote:
>
>>>> Lasse Clausen writes:
>>>> > I found the question perfectly straight forward already from the first
>>>> > post. Maybe it's to do with the fact that I fiddle with spacecraft
>>>> > trajectories and magnetic fields every day. Or maybe I'm just in a
>>>> > better mood than David...
>
>>>> No question I was in a bad mood after wasting most of the
>>>> afternoon looking for vestiges of earlier IDL installations
>>>> on my computer, but it seems to me that how you go about
>>>> adding magnetic vectors depends *entirely* on how you go
>>>> about plotting the trajectory.
>
>>>> In the proposed solution, I see we are just throwing
>>>> out the Z component of both the trajectory and the vector
>>>> field. Certainly this is the easiest way to proceed.
>>>> I just wonder if it is accurate though. :-)
>
>>>> Cheers,
>
>>>> David
>>>> --
>>>> David Fanning, Ph.D.
>>>> Fanning Software Consulting, Inc.
>>>> Coyote's Guide to IDL Programming:http://www.dfanning.com/
>>>> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
>
>>> We are not throwing away anything, we are merely projecting into the
>>> XY plane... ;-) You have to project somewhere as the computer screen
>>> is not capable of displaying 3D - nor is paper, incidentally. And the
>>> usual way to do this kind of thing is to provide three plots, one in
>>> the XY plane, one in XZ and one in YZ. You then have to assemble the
>>> 3D picture in your head.
>
>>> Alternatively, you can do the whole thing in "3D", using SURFACE to
>>> establish the coordinate system and then
>
>>> PLOTS, posx[i]+bx[i], posy[i]+by[i], posz[i]+bz[i], /T3D
>
>>> to plot the lines.
>
>>> Cheers
>>> Lasse Clausen
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| Re: How to plot the magnetic field vector along the trajectory [message #59258 is a reply to message #59133] |
Thu, 13 March 2008 05:40 |
duxiyu@gmail.com
Messages: 88
Registered: March 2007
|
Member |
|
|
I am not sure what the 'idldemo' means and cannot find its information
in IDL Help.
Could you introduce it in detail?
Du
On Mar 13, 1:00 am, mankoff <mank...@gmail.com> wrote:
> On Mar 12, 11:09 am, Lasse Clausen <la...@lbnc.de> wrote:
>
>
>
>> On 12 Mar, 15:45, David Fanning <n...@dfanning.com> wrote:
>
>>> Lasse Clausen writes:
>>>> We are not throwing away anything, we are merely projecting into the
>>>> XY plane... ;-) You have to project somewhere as the computer screen
>>>> is not capable of displaying 3D - nor is paper, incidentally. And the
>>>> usual way to do this kind of thing is to provide three plots, one in
>>>> the XY plane, one in XZ and one in YZ. You then have to assemble the
>>>> 3D picture in your head.
>
>>> Or, you could envision an object graphics solution with
>>> an "earth" and "satellite" revolving around it, casting
>>> a shadow trajectory onto the earth with a magnetic vector
>>> rotating about in the plane of the satellite.
>
>>> All I'm saying is, the question lacked enough detail,
>>> for whatever good reason, to know how to form a sensible
>>> answer. And that when you ask better questions, you get--
>>> generally--better answers.
>
>>> I agree that this question was borderline for such a
>>> response. Even I could tell English was not the first
>>> language. But coming, as it did, at the end of a long
>>> day and after several seriously bad questions from the
>>> past week, I just thought a reminder might be useful. :-)
>
>>> Cheers,
>
>>> David
>>> --
>>> David Fanning, Ph.D.
>>> Fanning Software Consulting, Inc.
>>> Coyote's Guide to IDL Programming:http://www.dfanning.com/
>>> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
>
>> As I said earlier, the question did not lack detail for me because I
>> have seen lots of these kind of plots before, so I was pretty sure
>> what was asked for. But I can also see that it would be confusing if I
>> hadn't seen these plots before.
>
>> More importantly, IDL can do that sort of thing? With shadows and all?
>> Object graphics I hear you say... Mmmm, so far I have ignored
>> everything involving object graphics. Well, maybe one fine day.
>
>> Cheers
>> Lasse Clausen
>
> Play around with "idldemo". There is a satellite orbiting the earth (I
> think with Ground Track). The earth is rotating. Clouds are rotating
> separately from Earth, etc.
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| Re: How to plot the magnetic field vector along the trajectory [message #59262 is a reply to message #59133] |
Wed, 12 March 2008 14:30 |
manodeep@gmail.com
Messages: 33
Registered: June 2006
|
Member |
|
|
Hello Du,
For a 2-d projection, try partvelvec.pro (http://
www.astro.washington.edu/deutsch-bin/getpro/library32.html?P ARTVELVEC)
velovect needs your data to be in a 2-d array format instead of the
scattered data points that you have.
Alternatively, the plots solution with a previous call to scale3 to
establish the axis and the
ranges should also be sufficient.
Cheers,
Manodeep
On Mar 12, 10:35 am, jdu <jdu.u...@gmail.com> wrote:
> Thanks a lot.
> I have found the internal procedure 'VELOVECT' which can produces a
> two-dimensional velocity field plot.
> It just meet my request.
> It seems that the 'iVector' can also produce the figures I want.
>
> Du
>
> On Mar 12, 10:23 pm, Lasse Clausen <la...@lbnc.de> wrote:
>
>> On 12 Mar, 14:26, David Fanning <n...@dfanning.com> wrote:
>
>>> Lasse Clausen writes:
>>>> I found the question perfectly straight forward already from the first
>>>> post. Maybe it's to do with the fact that I fiddle with spacecraft
>>>> trajectories and magnetic fields every day. Or maybe I'm just in a
>>>> better mood than David...
>
>>> No question I was in a bad mood after wasting most of the
>>> afternoon looking for vestiges of earlier IDL installations
>>> on my computer, but it seems to me that how you go about
>>> adding magnetic vectors depends *entirely* on how you go
>>> about plotting the trajectory.
>
>>> In the proposed solution, I see we are just throwing
>>> out the Z component of both the trajectory and the vector
>>> field. Certainly this is the easiest way to proceed.
>>> I just wonder if it is accurate though. :-)
>
>>> Cheers,
>
>>> David
>>> --
>>> David Fanning, Ph.D.
>>> Fanning Software Consulting, Inc.
>>> Coyote's Guide to IDL Programming:http://www.dfanning.com/
>>> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
>
>> We are not throwing away anything, we are merely projecting into the
>> XY plane... ;-) You have to project somewhere as the computer screen
>> is not capable of displaying 3D - nor is paper, incidentally. And the
>> usual way to do this kind of thing is to provide three plots, one in
>> the XY plane, one in XZ and one in YZ. You then have to assemble the
>> 3D picture in your head.
>
>> Alternatively, you can do the whole thing in "3D", using SURFACE to
>> establish the coordinate system and then
>
>> PLOTS, posx[i]+bx[i], posy[i]+by[i], posz[i]+bz[i], /T3D
>
>> to plot the lines.
>
>> Cheers
>> Lasse Clausen
|
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| Re: How to plot the magnetic field vector along the trajectory [message #59267 is a reply to message #59133] |
Wed, 12 March 2008 10:00 |
mankoff
Messages: 131
Registered: March 2004
|
Senior Member |
|
|
On Mar 12, 11:09 am, Lasse Clausen <la...@lbnc.de> wrote:
> On 12 Mar, 15:45, David Fanning <n...@dfanning.com> wrote:
>
>
>
>> Lasse Clausen writes:
>>> We are not throwing away anything, we are merely projecting into the
>>> XY plane... ;-) You have to project somewhere as the computer screen
>>> is not capable of displaying 3D - nor is paper, incidentally. And the
>>> usual way to do this kind of thing is to provide three plots, one in
>>> the XY plane, one in XZ and one in YZ. You then have to assemble the
>>> 3D picture in your head.
>
>> Or, you could envision an object graphics solution with
>> an "earth" and "satellite" revolving around it, casting
>> a shadow trajectory onto the earth with a magnetic vector
>> rotating about in the plane of the satellite.
>
>> All I'm saying is, the question lacked enough detail,
>> for whatever good reason, to know how to form a sensible
>> answer. And that when you ask better questions, you get--
>> generally--better answers.
>
>> I agree that this question was borderline for such a
>> response. Even I could tell English was not the first
>> language. But coming, as it did, at the end of a long
>> day and after several seriously bad questions from the
>> past week, I just thought a reminder might be useful. :-)
>
>> Cheers,
>
>> David
>> --
>> David Fanning, Ph.D.
>> Fanning Software Consulting, Inc.
>> Coyote's Guide to IDL Programming:http://www.dfanning.com/
>> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
>
> As I said earlier, the question did not lack detail for me because I
> have seen lots of these kind of plots before, so I was pretty sure
> what was asked for. But I can also see that it would be confusing if I
> hadn't seen these plots before.
>
> More importantly, IDL can do that sort of thing? With shadows and all?
> Object graphics I hear you say... Mmmm, so far I have ignored
> everything involving object graphics. Well, maybe one fine day.
>
> Cheers
> Lasse Clausen
Play around with "idldemo". There is a satellite orbiting the earth (I
think with Ground Track). The earth is rotating. Clouds are rotating
separately from Earth, etc.
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| Re: How to plot the magnetic field vector along the trajectory [message #59268 is a reply to message #59133] |
Wed, 12 March 2008 08:35 |
jdu
Messages: 7
Registered: February 2008
|
Junior Member |
|
|
Thanks a lot.
I have found the internal procedure 'VELOVECT' which can produces a
two-dimensional velocity field plot.
It just meet my request.
It seems that the 'iVector' can also produce the figures I want.
Du
On Mar 12, 10:23 pm, Lasse Clausen <la...@lbnc.de> wrote:
> On 12 Mar, 14:26, David Fanning <n...@dfanning.com> wrote:
>
>
>
>> Lasse Clausen writes:
>>> I found the question perfectly straight forward already from the first
>>> post. Maybe it's to do with the fact that I fiddle with spacecraft
>>> trajectories and magnetic fields every day. Or maybe I'm just in a
>>> better mood than David...
>
>> No question I was in a bad mood after wasting most of the
>> afternoon looking for vestiges of earlier IDL installations
>> on my computer, but it seems to me that how you go about
>> adding magnetic vectors depends *entirely* on how you go
>> about plotting the trajectory.
>
>> In the proposed solution, I see we are just throwing
>> out the Z component of both the trajectory and the vector
>> field. Certainly this is the easiest way to proceed.
>> I just wonder if it is accurate though. :-)
>
>> Cheers,
>
>> David
>> --
>> David Fanning, Ph.D.
>> Fanning Software Consulting, Inc.
>> Coyote's Guide to IDL Programming:http://www.dfanning.com/
>> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
>
> We are not throwing away anything, we are merely projecting into the
> XY plane... ;-) You have to project somewhere as the computer screen
> is not capable of displaying 3D - nor is paper, incidentally. And the
> usual way to do this kind of thing is to provide three plots, one in
> the XY plane, one in XZ and one in YZ. You then have to assemble the
> 3D picture in your head.
>
> Alternatively, you can do the whole thing in "3D", using SURFACE to
> establish the coordinate system and then
>
> PLOTS, posx[i]+bx[i], posy[i]+by[i], posz[i]+bz[i], /T3D
>
> to plot the lines.
>
> Cheers
> Lasse Clausen
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| Re: How to plot the magnetic field vector along the trajectory [message #59269 is a reply to message #59133] |
Wed, 12 March 2008 08:09 |
lasse
Messages: 48
Registered: February 2007
|
Member |
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|
On 12 Mar, 15:45, David Fanning <n...@dfanning.com> wrote:
> Lasse Clausen writes:
>> We are not throwing away anything, we are merely projecting into the
>> XY plane... ;-) You have to project somewhere as the computer screen
>> is not capable of displaying 3D - nor is paper, incidentally. And the
>> usual way to do this kind of thing is to provide three plots, one in
>> the XY plane, one in XZ and one in YZ. You then have to assemble the
>> 3D picture in your head.
>
> Or, you could envision an object graphics solution with
> an "earth" and "satellite" revolving around it, casting
> a shadow trajectory onto the earth with a magnetic vector
> rotating about in the plane of the satellite.
>
> All I'm saying is, the question lacked enough detail,
> for whatever good reason, to know how to form a sensible
> answer. And that when you ask better questions, you get--
> generally--better answers.
>
> I agree that this question was borderline for such a
> response. Even I could tell English was not the first
> language. But coming, as it did, at the end of a long
> day and after several seriously bad questions from the
> past week, I just thought a reminder might be useful. :-)
>
> Cheers,
>
> David
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.dfanning.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
As I said earlier, the question did not lack detail for me because I
have seen lots of these kind of plots before, so I was pretty sure
what was asked for. But I can also see that it would be confusing if I
hadn't seen these plots before.
More importantly, IDL can do that sort of thing? With shadows and all?
Object graphics I hear you say... Mmmm, so far I have ignored
everything involving object graphics. Well, maybe one fine day.
Cheers
Lasse Clausen
|
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| Re: How to plot the magnetic field vector along the trajectory [message #59270 is a reply to message #59133] |
Wed, 12 March 2008 07:45 |
David Fanning
Messages: 11724
Registered: August 2001
|
Senior Member |
|
|
Lasse Clausen writes:
> We are not throwing away anything, we are merely projecting into the
> XY plane... ;-) You have to project somewhere as the computer screen
> is not capable of displaying 3D - nor is paper, incidentally. And the
> usual way to do this kind of thing is to provide three plots, one in
> the XY plane, one in XZ and one in YZ. You then have to assemble the
> 3D picture in your head.
Or, you could envision an object graphics solution with
an "earth" and "satellite" revolving around it, casting
a shadow trajectory onto the earth with a magnetic vector
rotating about in the plane of the satellite.
All I'm saying is, the question lacked enough detail,
for whatever good reason, to know how to form a sensible
answer. And that when you ask better questions, you get--
generally--better answers.
I agree that this question was borderline for such a
response. Even I could tell English was not the first
language. But coming, as it did, at the end of a long
day and after several seriously bad questions from the
past week, I just thought a reminder might be useful. :-)
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
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