Referring to NaN or ±∞ (special floating point values) in ArcMap definition queries?

Question

I have by chance discovered how ArcMap displays special floating point values to the user.

• +∞ (positive infinity) is displayed as 1.#INF
• –∞ (negative infinity) would supposedly be displayed as -1.#INF — I haven't verified this one.

• NaN (not a number) is displayed as a right-aligned <Null> — not to be confused with left-aligned <Null>, which denotes NULL (missing values):

  

  (Get unique values in the field calculator does not list NaN at all, by the way.)

But I haven't discovered how to write layer definition queries to select rows based on these special values:

• ColumnName IS NULL will only select regular NULL values, but non NaN.
• ColumnName = 1.#INF is rejected as having invalid syntax.

Does anyone know how to do this?

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C# ArcObjects code snippet for storing a 1.#INF value to a table field (basic concept):

As requested. Since I'm no longer at work, the following is not the real code I used and I cannot test it right now, but it should produce the effect shown in the screenshot above:

ITable table = …;
int doubleFieldIndex = table.FindField(…);
IRow row = table.CreateRow(); 
row.Value[doubleFieldIndex] = double.PositiveInfinity;
row.Store();

Answer 1

In ArcGIS a single-precision floating-point number has a range of approximately -3.4E38 to 1.2E38.

If you are actually seeing the 1.#INF -1.#INF values displayed in your attribute table (or via MS Access when analyzing attributes) or grid statistics then these might be numbers that fall outside of the range supported by ESRI. And if these number do in fact fall outside of the supported range it is safe to say you will not be able to query for these values. You could try greater and less then the maximum and minimum (-3.4E38 to 1.2E38) and see what it returns but I am doubtful the query will work at all if the table/field contain unsuported range of values.

This source suggests that such values might have been imported from a 3-rd party non-ESRI application. You might need to convert the values to a supported range of values prior to importing to an ESRI product.

As for the NULL/NuN values, it would be usefull to know exactly what we are looking at in your example; An attrubute table of a grid, shapefile, geodatabase feature class, etc. For example, shapefiles cannot store NULL values so if a feature class thant contains NULL values is converted to a shapefile those are stored as various other values ("",0,NuN?, etc.) but when displayed in an ArcMap attribute table they are still visually represented as "<Null>". It's possible that the alignment of the NULLs in your attribute table is a such situation. I am only speculating about why you are able to query the left aligned NULLs but not the right-aligned NULLs but if this is a shapefile, try importing into a geodatabase then run the query again. Chances are that all of these will be converted to proper NULL values.