| Resampling large satellite (AVHRR) images to a grid [message #6520] |
Tue, 09 July 1996 00:00  |
Liam Gumley
Messages: 473
Registered: November 1994
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Senior Member |
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Hi folks,
I have the following data in 1-D arrays for an AVHRR scene:
latitude
longitude
brightness temperature
I can display the data as an image in satellite coordinates with
no problems (just REFORM the brightness temperature array).
However, I don't know of an efficient way to resample the image to
a lat/lon grid (say equidistant cylindrical). TRIANGULATE and REGRID
are far too slow (and are probably overkill) when used on every lat/lon
point. I have tried a few things with POLYWARP and POLY_2D but have
not come up with a satisfactory method yet.
Has anyone done something like this? I am looking for a *fast* algorithm
that will handle large AVHRR scenes (say 2048x208 pixels).
Cheers.
Liam.
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| Re: Resampling large satellite (AVHRR) images to a grid [message #6593 is a reply to message #6520] |
Thu, 11 July 1996 00:00  |
Hermann Mannstein
Messages: 22
Registered: September 1995
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Junior Member |
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Liam Gumley wrote:
>
> Hi folks,
>
> I have the following data in 1-D arrays for an AVHRR scene:
>
> latitude
> longitude
> brightness temperature
>
> I can display the data as an image in satellite coordinates with
> no problems (just REFORM the brightness temperature array).
>
> However, I don't know of an efficient way to resample the image to
> a lat/lon grid (say equidistant cylindrical). TRIANGULATE and REGRID
> are far too slow (and are probably overkill) when used on every lat/lon
> point. I have tried a few things with POLYWARP and POLY_2D but have
> not come up with a satisfactory method yet.
>
> Has anyone done something like this? I am looking for a *fast* algorithm
> that will handle large AVHRR scenes (say 2048x208 pixels).
Hallo Liam,
try to use the 'convert_coord' routine. Set your map and then
p = convert_coord(lon, lat, /data, /to_device)
image=fltarr( !d.x_size, !d.ysize)
and then
image(ps(0,*),ps(1,*)) = brightness_temperature
to fill holes use the dilate operator.
--
Regards,
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~
Hermann Mannstein Tel.: +49 8153 28-2503
Institut fuer Physik der Atmosphaere or -2558
DLR - Oberpfaffenhofen Fax.: +49 8153 28-1841
Postfach 1116 \ mailto:H.Mannstein@dlr.de
D-82230 Wessling \ 0 http://www.op.dlr.de/~pa64
Germany ________\/|________
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