comp.lang.idl-pvwave archive: archive » envi_get

Home » Public Forums » archive » envi_get_data

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

Re: envi_get_data [message #68165 is a reply to message #58173]

Wed, 30 September 2009 07:14

woods1
Messages: 24
Registered: August 2009

Junior Member

On 30 Sep., 11:39, Allard de Wit <allard.de...@wur.nl> wrote:
> woods1 wrote:
>> Hi,
>> i have a problem.
>> i try this: img = envi_get_data(fid=De_fid, dims=dims,pos=pos), but i
>
> Hi,
>
> Using ENVI_Get_Data() on such large images is really a bad idea.
> Trying to read the whole image will take more then 2Gb of memory (in
> case of 8bit data) and you will have trouble to fit it in memory on
> any 32 bit operating system.
>
> What you should do instead is use ENVI's tiling mechanism to read your
> image in chunks and loop over the number of tiles. Then resample each
> tile to be able to display it (or do whatever processing you want) and
> stitch the results together. So in pseudo code it should look like
> this:
>
> tile_ID = ENVI_Init_Tile(File_ID, NUM_TILES=num_tiles,
> INTERLEAVE=1, ....)
> FOR i=0L, num_tiles-1 DO BEGIN
> data = ENVI_Get_Tile(tile_ID)
> <processing data goes here>
> ENDFOR
> ENVI_Tile_Done, tile_ID
>
> Setting INTERLEAVE=1 ensures that you read your file line by line. It
> may be more efficient to use INTERLEAVE=0 but then you need to write
> some logic that handles the size of the tile that ENVI_Get_Tile
> returns, which depends on you memory settings.
>
> Hope this helps.
>
> Allard

My question is, what are the processing data here, when i will display
an image?

thank you

Report message to a moderator

[Message index]

		envi_get_data By: yychongzi on Mon, 21 January 2008 11:42
		Re: envi_get_data By: lbusett@yahoo.it on Fri, 25 January 2008 06:03
		Re: envi_get_data By: peter.eddy@shaw.ca on Fri, 25 January 2008 09:18
		Re: envi_get_data By: Jean H. on Fri, 25 January 2008 13:49
		Re: envi_get_data By: yychongzi on Fri, 25 January 2008 13:25
		Re: envi_get_data By: woods1 on Tue, 15 September 2009 00:12
		Re: envi_get_data By: Robert Moss, PhD on Mon, 14 September 2009 11:59
		Re: envi_get_data By: Andrew Rodger on Fri, 02 October 2009 06:29
		Re: envi_get_data By: woods1 on Thu, 01 October 2009 09:48
		Re: envi_get_data By: David Fanning on Wed, 30 September 2009 07:34
		Re: envi_get_data By: woods1 on Wed, 30 September 2009 07:14
		Re: envi_get_data By: wita on Wed, 30 September 2009 02:39
		Re: envi_get_data By: woods1 on Wed, 30 September 2009 01:25
		Re: envi_get_data By: woods1 on Wed, 30 September 2009 01:09
		Re: envi_get_data By: woods1 on Wed, 30 September 2009 01:02
		Re: envi_get_data By: Chris Jengo on Tue, 29 September 2009 07:40
		Re: envi_get_data By: David Fanning on Tue, 29 September 2009 06:18
		Re: envi_get_data By: lefsky@gmail.com on Mon, 12 November 2012 14:02
		Re: envi_get_data By: lefsky@gmail.com on Sun, 11 November 2012 20:22

Previous Topic:	Re: Beginner: Oplot line t^(-5/3)
Next Topic:	Curve Fitting Question

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Wed Oct 08 17:24:14 PDT 2025

Total time taken to generate the page: 0.00503 seconds