| Re: plot structured data II [message #24133] |
Wed, 14 March 2001 01:55 |
dw
Messages: 10
Registered: February 2001
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Junior Member |
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<Dear all,
<sorry for being unprecise last time.
<What I like to know is how to get access to the data in the structure or
<as David Fanning already said how to tear that structure apart and get a
<2d array for further use.
<The data in the structure is already gridded and I know how to use
<surface function but until now I can't find information how to use it
<with structured data sets.
<thanks a lot
<
< Dirk
Hi Dirk,
I got some help from Dave Fanning yesterday because I was trying to extract
an image from a structure so I could plot it.
In my particular case Dave suggested:
info.thisWindow->GetProperty, Image_Data=snapshot
and then you can use
Write_JPEG, filename, snapshot, True=1
to write the jpeg.
Here the display window object is in the 'info' structure and named
"thisWindow"
Don't know if this is helpful for you?
Dorthe
--
Posted from mail.isva.dtu.dk [192.38.88.3]
via Mailgate.ORG Server - http://www.Mailgate.ORG
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| Re: plot structured data II [message #24159 is a reply to message #24133] |
Mon, 12 March 2001 07:35  |
John-David T. Smith
Messages: 384
Registered: January 2000
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Senior Member |
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David Fanning wrote:
>
> Dirk Burose (dirk.burose@uni-bonn.de) writes:
>
>> sorry for being unprecise last time.
>> What I like to know is how to get access to the data in the structure or
>> as David Fanning already said how to tear that structure apart and get a
>> 2d array for further use.
>> The data in the structure is already gridded and I know how to use
>> surface function but until now I can't find information how to use it
>> with structured data sets.
>> thanks a lot
>
> Structures are de-referenced with a "dot". You want
> something like this:
>
> Surface, struct.mydata, struct.my_xvector, struct.my_yvector
>
> Sometimes structures have structures inside them. Then you
> use two dots, etc.:
>
> Surface, struct.mydata.grid, struct.mydata.xvec, struct.mydata.yvec
And sometimes you are using structures entirely inappropriately, like
when you really want an array instead, but are using read_ascii to get
it out of file. You might try crafting your own formatted read and
avoid read_ascii altogether, reading it directly into a 15xn array.
It's really pretty simple.
Read_ascii is best for multi-variable plots, not higher dimensional
data. If you are really stuck with a structure of fields with columns
of data the same length, and you'd like to convert it to a 2d array,
try:
for i=0,n_tags(st)-1 do $
if n_elements(a) eq 0 then a=1#st.(i) else a=[a,1#st.(i)]
But really, a better solution is to use the correct data type in the
first place.
Good luck,
JD
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| Re: plot structured data II [message #24160 is a reply to message #24159] |
Mon, 12 March 2001 07:05 |
davidf
Messages: 2866
Registered: September 1996
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Senior Member |
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Dirk Burose (dirk.burose@uni-bonn.de) writes:
> sorry for being unprecise last time.
> What I like to know is how to get access to the data in the structure or
> as David Fanning already said how to tear that structure apart and get a
> 2d array for further use.
> The data in the structure is already gridded and I know how to use
> surface function but until now I can't find information how to use it
> with structured data sets.
> thanks a lot
Structures are de-referenced with a "dot". You want
something like this:
Surface, struct.mydata, struct.my_xvector, struct.my_yvector
Sometimes structures have structures inside them. Then you
use two dots, etc.:
Surface, struct.mydata.grid, struct.mydata.xvec, struct.mydata.yvec
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155
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