Whilst a polyline may be digitized (flows) in the correct direction it's m-values may have become corrupted or were not properly calibrated when set.  You can use this quality control tool to identify problems with your measured data if route events are not plotting in an expected manner. 

This tool will only execute if your network is a PolylineM FeatureClass.

This tool does not create an error log file but adds a new field to the river network layer called MTrend. This is a text field that will contain 1 of 5 values:




The measure values along the polyline are not yet set (i.e the M values were "NaN").


All measure values are the same value along the polyline.


The measure values are increasing in value with the flow direction of the polyline.


The measure values are decreasing in value with the flow direction of the polyline.


The measure values are mixed such that there are sequences which increase, level off and/or decrease along the polyline.

The image below demonstrates three types of monotonic trends along a polyline. 

Examples of monotomic values