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Re: Geography and NOAA_14



The low-orbit weather satellites look straight down, so if
they are directly above you, they are sending back pictures
of you.

One gotcha is that most computers draw images from the top
to the bottom of the screen, so if the satellite pass is
south to north (e.g. NOAA-14 in the afternoon), the picture
will have south at the top, opposite to most maps. Most
programs have an option for this, or you can flip the image
in a graphics program.

Ground detail is usually of low contrast - the satellites
are designed to take pictures of brilliant white clouds
against dark ground. Ground detail on IR images is usually
nil. Great clouds, though...

The view may simply take some getting used to. You may not
be accustomed to what your area looks like from space. I
find this all the time when I show people my satellite
pictures, and geography doesn't get much more distinctive
than southwestern B.C.

The two pictures are visible and infrared. The pictures have
drastically different dynamic ranges, with the dark visible
image and the pale washed-out IR image. You'll need to
process them separately for best results. My homebrew
(homehacked?) software does slides and stretches, and
functions like "auto levels" in PhotoShop do the same
thing.

Some of the most dramatic pictures come from NOAA-12 and
NOAA-15 (the new one, called NOAA-K before its launch in
May). They go over at sunrise/sunset, so the clouds are lit
obliquely, and cast shadows.

BTW: I modified my Pro-43 scanner for a more appropriate
APT bandwidth by replacing the 455 kHz IF filter with a
10 nF capacitor. The results are breathtaking!

Laura Halliday VE7LDH        "Laisse le vent tout emporter..."
Grid: CN88hk IOTA: NA036          - Foly/Viennet

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