A lot of our datasets have a nodata value that is, or close to, -3.4028234663852886e+38.

Can anyone think of an easy way to say this out loud when we're discussing things?

Even "minus three times ten to the thirty-eight" is a bit of a mouthful. Something like "min float" would be shorter (I think that's what this value is supposed to represent), but is not strictly correct.

The best we've come up with so far is "minus three whatever", which is short, but not exactly scientific.

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    How about No Data? – Ian Turton Jul 8 '19 at 10:50
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    7f7f (some times shorted to 7f) is a term that I've seen used for the extreme values of float32. However, it would require explanation before usage. – Mikkel Lydholm Rasmussen Jul 8 '19 at 10:52
  • @IanTurton we want to distinguish between different nodata values - sometimes it's NaN, sometimes it's -999, sometimes it's -2147483648. – jon_two Jul 8 '19 at 10:58
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    Negative FLT_MAX (FLT_MIN has a negative exponent). -FLT_MAX should work as shorthand). – Vince Jul 8 '19 at 11:52
  • Who knows if "negative infinity" means the same or something else stackoverflow.com/questions/20016600/negative-infinity? – user30184 Jul 8 '19 at 18:30

Found on IBM (title: Single-precision floating-point (FLOAT or REAL))

A single-precision floating-point number is a 32-bit approximation of a real number. The number can be zero or can range from -3.4028234663852886e+38 to -1.1754943508222875e-38, or from 1.1754943508222875e-38 to 3.4028234663852886e+38.

That being said: i think you can name it as "negative maximum for float32" or to be short "-MF32"

  • The 'C' constant is FLT_MAX (the 32-bit character is implicit from FLT vice DBL). The goal is a scientific term, so making up a new one is weaker than using an existing one. – Vince Jul 8 '19 at 13:09
  • okay I did not understand the question that way, thanks for clarifying ! – pierre-m Jul 8 '19 at 13:24
  • That's really useful thanks. I had an idea it might be the lowest available float value because int rasters use -2147483648, which is -max int, but I wasn't sure. Don't know if -MF32 will catch on though. – jon_two Jul 9 '19 at 8:54

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