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Open-EO / openeo-processes

Interoperable processes for openEO's big Earth observation cloud processing.
https://processes.openeo.org
Apache License 2.0
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is_nodata(NaN) when NaN is used as no-data value ? #361

Closed soxofaan closed 2 years ago

soxofaan commented 2 years ago

In our geotrellis implementation IEEE754 NaN is used as no-data value for float raster cubes.

This creates a conflict in the definition of is_nodata(NaN): https://github.com/Open-EO/openeo-processes/blob/2cfd022fdc4826af89166d88880a873cbea20e90/is_nodata.json#L4

data is missing data, i.e. equals to null or any of the no-data values

=> is_nodata(NaN) = true

The special numerical value NaN as defined by IEEE Standard 754 is not considered no-data and must return false.

=> is_nodata(NaN) = false

m-mohr commented 2 years ago

Yeah, so this was meant to say that NaN is not implicitly also a no-data value as some may have understood it. Of course, it should possible that NaN is a nodata value if explicitly specified as such. I'll issue a PR to fix this.

m-mohr commented 2 years ago

See PR #362