Pixel values are obtained through a look-up table that
relates the original source data, 2-byte integers
representing elevation or bathymetry in meters above or
below sea-level, to color. The mapping for ice-covered
pixels is made using a different algorithm than for pixels
not covered by ice. This is the algorithm used for ice-
covered pixels:
if depth < 0 then color = 0x60,0x60,0x60
if depth < 500 then color = 0x80,0x80,0x80
if depth < 1000 then color = 0xa0,0xa0,0xa0
if depth < 1500 then color = 0xc0,0xc0,0xc0
if depth < 2000 then color = 0xe0,0xe0,0xe0
if depth < 32767 then color = 0xff,0xff,0xff
This is the algorithm used for pixels not covered by ice:
if depth < -5000 then color = 0x00,0x00,0x00
if depth < -4000 then color = 0x00,0x00,0x10
if depth < -3000 then color = 0x00,0x00,0x20
if depth < -2000 then color = 0x00,0x00,0x30
if depth < -1000 then color = 0x00,0x00,0x40
if depth < -900 then color = 0x00,0x00,0x50
if depth < -800 then color = 0x00,0x00,0x60
if depth < -700 then color = 0x00,0x00,0x70
if depth < -600 then color = 0x00,0x00,0x80
if depth < -500 then color = 0x00,0x00,0x90
if depth < -400 then color = 0x00,0x00,0xa0
if depth < -300 then color = 0x00,0x00,0xb0
if depth < -200 then color = 0x00,0x00,0xc0
if depth < -190 then color = 0x00,0x00,0xd0
if depth < -180 then color = 0x00,0x00,0xe0
if depth < -170 then color = 0x00,0x00,0xf0
if depth < -160 then color = 0x00,0x00,0xff
if depth < -150 then color = 0x00,0x10,0xff
if depth < -140 then color = 0x00,0x20,0xff
if depth < -130 then color = 0x00,0x30,0xff
if depth < -120 then color = 0x00,0x40,0xff
if depth < -110 then color = 0x00,0x50,0xff
if depth < -100 then color = 0x00,0x60,0xff
if depth < -90 then color = 0x00,0x70,0xff
if depth < -80 then color = 0x00,0x80,0xff
if depth < -70 then color = 0x00,0x90,0xff
if depth < -60 then color = 0x00,0xa0,0xff
if depth < -50 then color = 0x00,0xb0,0xff
if depth < -40 then color = 0x00,0xc0,0xff
if depth < -30 then color = 0x00,0xd0,0xff
if depth < -20 then color = 0x00,0xe0,0xff
if depth < -10 then color = 0x00,0xf0,0xff
if depth < 0 then color = 0x00,0xff,0xff
if depth < 10 then color = 0x00,0xff,0x00
if depth < 20 then color = 0x10,0xff,0x00
if depth < 30 then color = 0x20,0xff,0x00
if depth < 40 then color = 0x30,0xff,0x00
if depth < 50 then color = 0x40,0xff,0x00
if depth < 60 then color = 0x50,0xff,0x00
if depth < 70 then color = 0x60,0xff,0x00
if depth < 80 then color = 0x70,0xff,0x00
if depth < 90 then color = 0x80,0xff,0x00
if depth < 100 then color = 0x90,0xff,0x00
if depth < 110 then color = 0xa0,0xff,0x00
if depth < 120 then color = 0xb0,0xff,0x00
if depth < 130 then color = 0xc0,0xff,0x00
if depth < 140 then color = 0xd0,0xff,0x00
if depth < 150 then color = 0xe0,0xff,0x00
if depth < 160 then color = 0xf0,0xff,0x00
if depth < 170 then color = 0xff,0xff,0x00
if depth < 180 then color = 0xff,0xf0,0x00
if depth < 190 then color = 0xff,0xe0,0x00
if depth < 200 then color = 0xff,0xd0,0x00
if depth < 300 then color = 0xff,0xc0,0x00
if depth < 400 then color = 0xff,0xb0,0x00
if depth < 500 then color = 0xff,0xa0,0x00
if depth < 600 then color = 0xff,0x90,0x00
if depth < 700 then color = 0xff,0x80,0x00
if depth < 800 then color = 0xff,0x70,0x00
if depth < 900 then color = 0xff,0x60,0x00
if depth < 1000 then color = 0xff,0x50,0x00
if depth < 2000 then color = 0xff,0x40,0x00
if depth < 3000 then color = 0xff,0x30,0x00
if depth < 4000 then color = 0xff,0x20,0x00
if depth < 5000 then color = 0xff,0x10,0x00
if depth < 6000 then color = 0xff,0x00,0x00
if depth < 32767 then color = 0xff,0x00,0x00