Re: Cold anomaly in NE Portugal


Simon Proud <simon.proud@...>
 

Are you converting the data into an imprecise data type (such as 8bit int)?
Depending on the scaling you apply it could be that the values in that
region (~350K) are too high for the data type and so 'roll over' into a
very low value. This happens to us occasionally when calculating
reflectance in the twilight region.

/random guess

Cheers,
Simon

On Sun, Sep 23, 2012 at 11:07 AM, nick <dctower@nildram.co.uk> wrote:

On 23/09/2012 08:34, Alan Sewards wrote:
Nick,

Unless you are using an inverted palette, black on a IR image
translates into hot, not cold. It looks to me as a small hot spot,
probably a fire as suggested by Terence, but it is odd that it shows up
best in Ch4 and much less so in Ch9.

Best regards - Alan S

On 22/09/2012 9:59 PM, nick wrote:
Evening all,

Any one else see the _very_ cold (black) area in NE Portugal in the last
few IR images? Very obvious in Channel 4 from about 18:30 to 19:15?

Also on several other wave-lengths but not so obvious.

Any ideas as to what/why?

Regards

Nick

Yes, not sure how I got hot/cold inverted :-)

Regards

Nick


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