Reclassifying a Curvature raster

Question

I am trying to reclassify a profile curvature raster generated by the Curvature tool available in ArcGIS into three classes following the tool help where it is reported that;

...a negative value indicates the surface is upwardly convex at that cell. A positive profile indicates the surface is upwardly concave at that cell. A value of 0 indicates the surface is flat.

My Curvature raster' values range between -4.726 to 0.543. By supplying class breaks (-4.726, 0, 0.543) in the Reclassify tool yield spurious results where pixels having values == 0, as separately identified by raster calculator, are more in numbers (pixel count) than it should be!

What are optimal class break values to get accurate reclassified Curvature raster?

Answer 1

It sounds like you want a Sign function, which I don't think exists in the Raster Calculator. Instead, you could nest Con functions, like this:

Con("ras"==0,0, Con("ras"<0,-1, 1))

From the help on the Reclassify tool, "the higher end of the lower input range is inclusive, and the lower end of the higher input range is exclusive."