Wednesday, May 14, 2008

Using Update Attributes to Set Contour Elevation

An alternative method to set the elevation value of a contour line is to use GeoMedia's Update Attributes.

  1. Use the Selection Tool to select one or more contour lines with the same elevation.
  2. From the GeoMedia's pulldown menus, select Edit > Attribute > Update Attributes.

    The Update Attributes dialog appears.


  3. In the Update Attributes dialog, expand the Select Set nodes and select the feature name.
  4. On the right side of the Update Attributes dialog, click in the Value field of the feature's geometry field, e.g. LinearGeometry.
  5. Click Expression.

    The Expression dialog box appears.


  6. In the Categories list box, click Geometry.
  7. In the Functions list box, double click the function SETZ.
  8. In the Attributes list box, double click the attribute Input.{GeometryFieldName} e.g. Input.LinearGeometry.

    The Expression field should read like this:
    SETZ(Input.LinearGeometry)

  9. Type in a comma before the closing parentheses.
  10. Type in the elevation to set in the Expression field, e.g. 1000. The elevation should be in the units of the GeoWorkspace Coordinate System's Vertical Storage Unit.

    The Expression field should now read something like this:
    SETZ(Input.LinearGeometry,1000)

    Note: If the elevation you want to type in is not in the Coordinate System's Vertical Storage units, then you will have to do a conversion yourself.

  11. Click OK.

    The selected contour line's elevation is adjusted to the new elevation.



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