To perform an Overlay operation
- Connect to
the features sources to compare.
To use a feature layer,
you must add it to your map. To use a feature class, you must connect
to its data store, but you need not add it to the map.
- On the Overlay Analysis dialog box - Source and Overlay Type page,
specify the following:
- Click Next.
- On the Overlay Analysis dialog box - Set Output and Settings page,
specify the following:
- Output: Specify
the name and location of the SDF file that will contain the result
of the Overlay operation.
- Layer Name:
Specify the name of the Display Manager layer
that will contain the result of the Overlay operation.
- Sliver Tolerance:
Specify which slivers become separate features and which are joined
with a neighboring polygon. Set the units for the tolerance setting,
then set the maximum and minimum values. To see recommended values,
click Suggest. To ignore slivers
altogether, click Don’t Remove Slivers.
When the Overlay operation
splits features to produce the output layer, it tries to eliminate
polygons that are smaller than the specified tolerance settings.
Such polygons might have been present in the sources, and some may
be produced by the Overlay operation itself. The
elimination of slivers affects the output layers only.
Polygons that are larger
than the Maximum value become separate
features in the output layer. Polygons that are smaller than the Minimum value
are merged with a neighboring polygon. The Overlay operation checks
polygons that fall between the two values to see how wide they are. If
they are very narrow, they are merged with a neighboring polygon.
the resulting polygons are not as desired, try adjusting the tolerance values
and repeating the Overlay operation.
- Ordinate Tolerance:
Specify how far apart two nodes or vertices of a line or polygon
must be to be treated as separate points in the output layer. Set the
units for the tolerance setting, then set the Length.
Any two points that are
closer together than the Length value
are treated as a single point in the output layer.
- Output Properties:
Specify which properties from the Source and
(if applicable) Overlay are included in the
“All” adds all properties
to the resulting layer. “Identifiers” adds only the primary identifiers
(primary keys or unique fields, such as Feature_ID). “Non-Identifiers”
adds only the non-key attributes (such as Land_Value or Speed_Limit,
for example). If you add only non-identifiers, the overlay operation
generates primary identifiers for the features in the resulting layer.
- Click Finish to
perform the Overlay.
The Overlay operation
creates a new layer representing the result of the comparison. The
new layer is displayed in the map and in Display Manager.
The same data is written to the SDF file you specified.
To see just the Overlay output,
deselect the check boxes for the other layers in Display