001609 : Some features are farther than 30 degrees apart. You must project this data to a Projected Coordinate System to run this analysis.

Description

When your input features are not projected (that is, when coordinates are given in degrees of latitude and longitude) or when the output coordinate system is set to a geographic coordinate system, or when you specify an output feature class path to a feature dataset that has a geographic coordinate system spatial reference, distances will be computed using chordal measurement. Unfortunately, Chordal distance measurements only provide a good estimate of geodesic distances smaller than about 30 decimal degrees.

Solution

Project your data to a projected coordinate system and rerun the analysis, or remove locational outliers (features far from all other features) prior to running this analysis.