Version 7 of Enhancing Satellite Weather Images
Updated 2005-08-28 17:55:51Aug 28 2005 SRIV After noticing that some of the NOAA enhance satellite images were being delayed around 1-2 hours, I decided to try to enhance the higher resolution black & white images.
This script will download and display the latest North America image, then enhance the image with colors. Heres what the output looks like: http://server.linuxsys.net/images/latest_eastir_eh.gif compared to NOAA's image http://server.linuxsys.net/images/satimg.jpg .
RS Here's a snapshot of the Katrina Category 5 Hurricane (between Florida and N.O.) on 2005-08-28:
# satenhance.tcl 08-28-2005 Steve Redler IV
package require Tk
package require http
canvas .c -width 1000 -height 900
pack .c
proc colorize {image} {
# get image sizes
set width [image width $image]
set height [image height $image]
for {set y 0} {$y < $height} {incr y} {
puts "row=$y"
set row {}
for {set x 0} {$x < $width} {incr x} {
# save transparency
lappend trans $x $y [$image transparency get $x $y]
# compute the new color
foreach {r g b} [$image get $x $y] break
if {$r > 254} {
#white
lappend row [format #%02x%02x%02x 255 255 255]
continue
} elseif {$r > 240} {
#dkgrey
lappend row [format #%02x%02x%02x 50 50 50]
continue
} elseif {$r > 230} {
#ltgreen
lappend row [format #%02x%02x%02x 132 247 128]
continue
} elseif {$r > 226} {
#green
lappend row [format #%02x%02x%02x 60 214 18]
continue
} elseif {$r > 222} {
#ltpink
lappend row [format #%02x%02x%02x 249 127 124]
continue
} elseif {$r > 218} {
#pink
lappend row [format #%02x%02x%02x 255 91 98]
continue
} elseif {$r > 214} {
#ltred
lappend row [format #%02x%02x%02x 217 0 0]
continue
} elseif {$r > 210} {
#red
lappend row [format #%02x%02x%02x 150 0 0]
continue
} elseif {$r > 205} {
#dkred
lappend row [format #%02x%02x%02x 114 0 0]
continue
} elseif {$r > 200} {
#ltble
lappend row [format #%02x%02x%02x 0 215 230]
continue
} elseif {$r > 195} {
#blue
lappend row [format #%02x%02x%02x 0 100 170]
continue
} elseif {$r > 190} {
#dkblue
lappend row [format #%02x%02x%02x 0 11 100]
continue
} elseif {$r > 185} {
#ltyellow
lappend row [format #%02x%02x%02x 240 240 0]
continue
} elseif {$r > 180} {
#yellow
lappend row [format #%02x%02x%02x 160 160 0]
continue
} elseif {$r > 170} {
#dkyellow
lappend row [format #%02x%02x%02x 100 100 0]
continue
} else {
lappend row [format #%02x%02x%02x $r $r $r]
}
}
# update the row of the image
satimage put \{$row\} -to 0 $y
update
}
# restore transparency
foreach {x y t} $trans { $image transparency set $x $y $t }
}
set imagedata [http::data [http::geturl http://www.ssec.wisc.edu/data/east/latest_eastir.gif]]
image create photo satimage -data $imagedata
.c create image 0 0 -image satimage -tag imgtag -anchor nw
update
after 100 [colorize satimage]
update
# write the result to disk
satimage write latest_eastir_eh.gif -format gif