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plazi / GoldenGATE-Imagine

A GUI Tool For Freeing Text and Data from PDF Documents
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360/360 long lat for unknown lat long? #13

Open myrmoteras opened 3 years ago

myrmoteras commented 3 years ago

@gsautter what it the reason that we have so many 360/360 lat/long pairs in our MC?

gsautter commented 3 years ago

The question in the ticket title is pretty much the answer ... yes, 360/360 is the substitute for "unknown lat/long", just as minus the radius of the earth is the indicator for "unknown elevation".

This is the kind of encoding required for numbers that can take both positive and negative values, as well as zero ... there is no just other simply way of encoding "empty" in a numeric database field, an for the expected range searches that are likely on these fields, numeric fields are so much more efficient from a database point of view than a string based encoding that at least back in 2009 it seemed like the best way to go, and still feels that way to this day.

A strictly positive number like specimen count would allow encoding "unknown" as -1 (as generally done in the JRE API), but that obviously does not work for lat/long or elevation, where -1 is a completely plausible value to occur in the data these fields are intended to hold, so other out-of-range values need to be used.