000869 : Z factor: The Z units of the output geographic spatial reference are undefined. A default Z factor of 1 was used.

Description

Surface calculations in geographic coordinate systems may not create valid output results when the horizontal ground units and vertical elevation units use a different measure. This typically occurs when the horizontal (x,y) units are geographic and the vertical (z) units are a linear unit (for example, feet or meters).

The tool was not able to determine an appropriate value for the z-factor because the z-coordinate unit is not defined. By default a value of 1.0 will be used for the z-factor.

Since the length of a degree of longitude changes with latitude, you will need to specify an appropriate z-factor for that latitude.

Solution

• If the provided default value of 1.0 is not acceptable, specify an appropriate z-factor for the tool parameter.

  If the output spatial reference contains the correct vertical coordinate system, an appropriate z-factor can be calculated.

• Alternatively, use a projected coordinate system where the x,y and z-units are the same.

• You can use the Define Projection tool or Project Raster tool to apply the proper vertical coordinate system to the input data.