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hannahwhy/convert.rb

Created November 24, 2012 23:16
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PNG -> GeoTIFF conversion for Blue Marble PNGs
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convert.rb
def trans_lat(lat)
lat =~ /([0-9]+)([NS])/
num, dir = $1.to_i, $2
dir == 'S' ? -num : num
end
def trans_long(long)
long =~ /([0-9]+)([EW])/
num, dir = $1.to_i, $2
dir == 'W' ? -num : num
end
data = if ARGV.length > 0
ARGV.map { |f| File.read(f) }.join("\n")
else
$stdin.read
end
data.split("\n").each do |row|
fn, ul_lat, ul_long, lr_lat, lr_long, res = row.split("\t")
dst = fn.sub(File.extname(fn), '.tiff')
uly = trans_lat(ul_lat)
ulx = trans_long(ul_long)
lry = trans_lat(lr_lat)
lrx = trans_long(lr_long)
cmd = "gdal_translate -a_srs WGS84 -a_ullr #{ulx} #{uly} #{lrx} #{lry} #{fn} /gtiff/output/#{dst}"
puts cmd
`#{cmd}`
end
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manifest
world.topo.200408.3x21600x21600.A1.png 90N 180W 0N 90W 240
world.topo.200408.3x21600x21600.A2.png 0N 180W 90S 90W 240
world.topo.200408.3x21600x21600.B1.png 90N 90W 0N 0W 240
world.topo.200408.3x21600x21600.B2.png 0N 90W 90S 0W 240
world.topo.200408.3x21600x21600.C1.png 90N 0W 0N 90E 240
world.topo.200408.3x21600x21600.C2.png 0N 0W 90S 90E 240
world.topo.200408.3x21600x21600.D1.png 90N 90E 0N 180E 240
world.topo.200408.3x21600x21600.D2.png 0N 90E 90S 180E 240
@hannahwhy
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hannahwhy commented Nov 24, 2012

More info and source data:

http://visibleearth.nasa.gov/view.php?id=73776
http://eoimages.gsfc.nasa.gov/images/imagerecords/73000/73776/readme.pdf (extent data)

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