..Warning. Max height difference exceeded..

Problem / Issue

When you add data to a surface and create/rebuild the surface, it checks the maximum and minimum elevations.  If this exceeds the lowest and/or highest known points on earth (above and below sea level) a message displays in the CSD Notifications panel:

 WARNING.  Max height difference exceeded <Surface Name>

You can confirm the elevation issue by opening the Create/Edit Surface form, selecting the Statistics tab (tab on the left) and clicking on the Update button.  Either the Maximum height or Minimum height will be a large value.

This is a warning only message.  Note that the software typically tries to calculate over this full range, so it may take a long time to build/rebuild the surface, especially if it's drawing the contours.

Solution

To fix, you will need to locate the high/low data used to build the surface and remove it, then run the Build Surface command.  If the issue is coming from a design (string based model) surface, then it will be important to review the design strings and cross sections to see where high or low elevations are occurring.  A common issue that can result in this issue is having the start, end or a portion of the design residing outside of the sampled surface for the string.  For this problem, the resolution is to either increase the surface extents or change the alignment geometry.

Tools for Surface Display
There are some tools to restrict the surface display:

• In the Create/Edit Surface form > Outputs > Build Controls tab are two options to:
  • Ignore contours greater than:  this will stop drawing contours above a certain elevation (it does NOT limit the actual surface elevation)
  • Ignore contours less than: this will stop drawing contours below a certain elevation (it does NOT limit the actual surface elevation)