comp.lang.idl-pvwave archive: archive

Home » Public Forums » archive » Shape to raster

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

Re: Shape to raster [message #78178 is a reply to message #78139]

Mon, 31 October 2011 07:54

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Fabzou writes:

> I have an other question though. How will the IDLanROI object
> "understand" the XY coordinates [0.5,0.5]? In my conception, these
> coordinates correspond to the center of the first down left pixel, but
> my first tests tend to show that this may not be the case...

Oh, my gosh! I just spent a week worrying about this
in conjunction with an update of my Active Contouring
software! I don't use an IDLanROI object there, because
I want to do this myself and completely understand what
I am doing. In *my* ROI, the [0.5,0.5] location would
indeed be the center of the first pixel. I don't know
off-hand what the IDLanROI object will do. And I have
no compelling interest in looking into it this morning,
either. It makes my head hurt. :-)

Cheers,

David

P.S. If you are going to test this, however, I would
test with the values 0.45 and 0.55, not the value 0.5.
At some point, you are going to have to do some rounding
if you want image or device coordinates. The question
you want to answer is how the rounding is done.

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

Report message to a moderator

[Message index]

		Shape to raster By: Fabzou on Wed, 26 October 2011 09:52
		Re: Shape to raster By: Fabzou on Mon, 31 October 2011 09:17
		Re: Shape to raster By: ben.bighair on Mon, 31 October 2011 09:09
		Re: Shape to raster By: Fabzou on Mon, 31 October 2011 09:07
		Re: Shape to raster By: David Fanning on Mon, 31 October 2011 07:54

Previous Topic:	Re: unable to set time attribute for netCDF in IDL
Next Topic:	Re: wind fields on map

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Oct 10 22:43:30 PDT 2025

Total time taken to generate the page: 0.63933 seconds