comp.lang.idl-pvwave archive: archive » IDL Average Value Graphs

Home » Public Forums » archive » IDL Average Value Graphs

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: IDL Average Value Graphs [message #61497 is a reply to message #61413]

Thu, 17 July 2008 18:11

andybohn
Messages: 5
Registered: July 2008

Junior Member

On Jul 17, 5:52 pm, Jean H <jghas...@DELTHIS.ucalgary.ANDTHIS.ca>
wrote:
>> I needed the 2d coordinates because I'm dealing with FITS images, so I
>> need to grab the value of each of the pixels in a given region, unless
>> I'm missing an easier way to do this.
>
> I am not familiar with FITS images, but I strongly believe you are
> missing an important IDL feature.
> Read the help file under "Understanding Array Subscripts "
>
> **************
> Elements of multidimensional arrays also can be specified using only one
> subscript, in which case the array is treated as a vector with the same
> number of points.
> A0,0 A0,1
> A0,1 A1,1
> A0,2 A1,2
> In the 2 by 3 element array, A, element A[2] is the same element as A[0,
> 1], and A[5] is the same element as A[1, 2].
> ***************
>
> I have one more question about POLYFILLV. If a line goes
>
>> through a pixel, does it not include this pixel in the region? Does
>> it include it if it is more than half way inside the region? If so,
>> what happens to perfectly split pixels?
>
>> Thanks a lot for the help,
>> Andy
>
> the algorithm used is a bit fuzzy.... people, including myself, often
> complain here that some pixels get selected while other do not (make a
> few tests). As David mentioned, IDLgrROI provides better results. Now it
> all depends on what you are doing... if you select a few 100 000 pixels,
> you might not care that much about having a few extra/missing pixels!
>
> Jean

Ah, I was not aware of this. I didn't know that you could access
elements in a 2d array by calling the 1d equivalent. This isn't
something I've seen in other languages. thanks for the tip

Report message to a moderator

[Message index]

		IDL Average Value Graphs By: andybohn on Tue, 15 July 2008 13:51
		Re: IDL Average Value Graphs By: David Fanning on Thu, 17 July 2008 08:33
		Re: IDL Average Value Graphs By: andybohn on Thu, 17 July 2008 10:55
		Re: IDL Average Value Graphs By: Jeremy Bailin on Wed, 16 July 2008 11:18
		Re: IDL Average Value Graphs By: andybohn on Thu, 17 July 2008 18:11
		Re: IDL Average Value Graphs By: David Fanning on Thu, 17 July 2008 16:02
		Re: IDL Average Value Graphs By: Jean H. on Fri, 18 July 2008 10:20
		Re: IDL Average Value Graphs By: Jean H. on Thu, 17 July 2008 14:52
		Re: IDL Average Value Graphs By: David Fanning on Thu, 17 July 2008 12:09
		Re: IDL Average Value Graphs By: andybohn on Thu, 17 July 2008 11:02

Previous Topic:	Something Has Changed
Next Topic:	QHULL/VORONOI question

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Wed Oct 15 14:11:35 PDT 2025

Total time taken to generate the page: 0.56068 seconds