Finding changes in slope direction

Having an unchanging direction of slope is referred to as monotonicity. Elevations should have a set trend in an upward, downward, or level direction. For example, river features should flow only in one direction. When the slope begins to move in a different direction from its original course, monotonicity errors are created.


A vertical coordinate system must be defined for the feature class you want to use with this check.

The Slope Direction Change (Monotonicity) check finds features that represent monotonic errors. These are features where the direction in the slope has changed. The check can be run on an entire feature class, a subtype, or a set of features selected using an SQL query.

Once you have defined the criteria for the check, you can configure the notes and a severity rating. The notes allow you to provide a more specific description for the feature that has been written to the Reviewer table and are copied to the Notes field in the Reviewer table. The severity rating allows you to indicate how important the results from a check are in terms of your quality assurance/quality control processes. The lower the number, the greater the priority the check's results have.

  1. Start ArcMap.
  2. On the main menu, click Customize > Toolbars > Data Reviewer.
  3. Click the Select Data Check drop-down arrow on the Data Reviewer toolbar, click the plus sign (+) next to Z Value Checks, then click Slope Direction Change (Monotonicity) Check.

    The Slope Direction Change (Monotonicity) Check Properties dialog box appears.

    Slope Direction Change (Monotonicity) Check Properties dialog box
  4. Click the Feature Class/Subtype drop-down arrow to choose the feature class and subtype on which to run the check.
  5. To run the check on the entire feature class and save this setting, check the Always Run on Full Database check box.
  6. To run the check on specific features in a feature class, click SQL to construct an SQL query.
  7. If necessary, check the check boxes that correspond to the features that should be recorded in the Reviewer table.

    This is the feature class that contains the z-values you want to evaluate.

    • Level Features (From = To)—Finds all features where the from z-value is equal to the to z-value or do not trend in a consistent direction.
    • Downhill Features (From > To)—Finds all non-monotonic features and features where the from z-value is greater than the to z-value
    • Uphill Features (From < To)—Finds all non-monotonic features and features where the from z-value is less than the to z-value

    If you do not choose an option when you run the check, only the monotonicity errors will be reported, regardless of a feature's slope direction or if it is level.


    This check uses the end nodes of a polyline part as its point of reference.

  8. If necessary, type descriptive text for the check results in the Notes text box in the Reviewer Remarks area.
  9. If necessary, click the Severity drop-down arrow and choose a value that indicates the priority of the check's results in the Reviewer Remarks area.

    The severity indicates the importance of the check result. The values range from 1 to 5, with 1 being the highest priority and 5 being the lowest.

  10. Click OK.
  11. Click the Run Data Check button Run Data Check on the Data Reviewer toolbar.

    The Features to Validate dialog box appears.

    Features to Validate dialog box
  12. Choose an option in the Features to Validate area.
    • Selection Set—The check is run on the features that are currently selected in the map.
    • Current Extent—The check is run on the current map extent, which is controlled by the map scale.
    • Definition Query—The check is run on the features that are displayed based on definition queries that have been created for the feature class.
    • Full Database—The check is run on all the features in the feature class.
  13. To run the check only on features that have been edited in a versioned workspace, check the Changed Features Only check box.

    The Changed Features Only option is available only for a versioned database.

  14. Click OK.

    The check is run on the extent specified on the Features to Validate dialog box.

    When the check finishes, a check results dialog box appears.

  15. Do one of the following:
    • If you want to browse the results in the Browse Features window, choose the Browse Results option.
    • If you have started a Reviewer session and want to record the results in the Reviewer table, choose the Write to Reviewer Table option.
  16. Click OK.

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