| Re: problem with subset one image by another [message #59438 is a reply to message #59335] |
Wed, 26 March 2008 19:10   |
negra
Messages: 9
Registered: March 2008
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Junior Member |
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On 27 мар, 01:52, James Kuyper <jameskuy...@verizon.net> wrote:
> negra wrote:
>> On 22 ÍÁÒ, 22:12, David Fanning <n...@dfanning.com> wrote:
>>> negra writes:
>>> Well, there probably is nothing easier than this in IDL,
>>> either, so I think folks are either waiting for you to
>>> realize this or waiting for you to explain in a little
>>> more detail exactly what it is you are trying to do. :-)
>
>>> Cheers,
>
>>> David
>>> --
>> I have a large number of georeferenced MODIS images in ENVI. And it's
>> just attempt to get rid from leaving for area of interest of
>> territory.
>
> Are these Level 2 images, or Level 3? Level 2 products are organized
> around 5-minute granules of data, and are generally in HDF-EOS Swath
> format. For best results, a Geolocation (MOD03 or MYD03) file should be
> used for georeferencing such data.
>
> Level 3 images are rebinned to a rectangular grid in som particular map
> projection (often sinusoidal), and are stored in HDF-EOS Grid format.
>
> The techniques that should be used are somewhat different in the two cases.
>
> And, as David said, we need a whole lot more details about what it is
> you are trying to do.
It's images processed from Level1 or Level 0 to Level 2 products. Some
I take them from our receiving station, others, when we have problems
with receiving, I take as 5-minute granules of data as Level 0 (pds)
from ftp. Then I process them till level 2 product. And georefernce in
IDL (because I have IDL routine for processing a large number of data)
to geografical projection. And then I calculate indexes what I need.
For example it's Vegetation, Snow, Dust and other calculations.
For different arithmetic procedures in ENVI&IDL I must have same size
images. May be it would be easier if I will subset by coordinates of
four corner?
But some times images smaller than the area of interest(AOI). Because
AOI it's the territory of whole our country. In this case, I have
procedure of filling by null data till needed size. But in future I
plan to use this procedure (If I wrote it :-)) certainly) to smaller
regions.
Gulshat,
P.S. Excuse me, for my English If something wrong.
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