|
The topology column of the Layer Settings screen define restrictions on how geometry can be drawn on a layer. There is only one topology rule at the time this help file was last updated but more will soon be added to help users maintain the integrity of their layers. Unlike most of the other layer settings, topology rules are stored in the layer file rather than the map file so that the layer designer can assure that these rules travel with the layer as it might be used in multiple maps. That is why users are prompted to first lock the layer for editing before gaining access to this screen.
Auto Split
Check this box if polylines on this layer should only be connected at end points. When this box is checked, any attempt to connect a new line or symbol to an existing polyline will cause the existing polyline and existing feature to be automatically split into two polylines, each belonging to its own feature. One of the two polylines remains as a sibling of the original feature while the other is adopted by a new feature created as a duplicate of the original feature.
Topology Group
If users select an optional topology group then any layers assigned to this same group will be treated as if they are all part of the same layer when it comes to connectivity checking. So if the water valves layer and water lines layer are both set to auto split and both part of the same "Water" topology group, then any time a valve is placed on an existing polyline, the polyline will be automatically split at that point even though it is on a different layers. Users can create any name desired for the topology group. The names in the list are only a suggestion. The topology group names should not be confused with layer categories.
Special Feature Splitting Situations
When an existing feature is split, a new feature is automatically created that is a duplicate of the first feature. The only exception is that any auto number fields get incremented, and address range layers get assigned new low and high house numbers calculated based on the point of the break.
Visibility/Locking
The Auto Split checking is performed on all layers of the same topology group even if those layers are not currently visible. Users will be prompted to lock those other layers in the event that a split is needed on a layer that is not yet locked.
Areas
The Auto Split checking does not apply to areas. Only polylines are split and only when a polyline vertex, of symbol is snapped to them.
Lines that Cross
If a new line is drawn across an existing line without actually snapping to the line then the lines are considered to cross without connecting. This is common when line networks pass at different elevations.
|