Function Description

An object used to check that the point, line, Region Dataset itself, and the different types of Dataset do not conform to the Topology Rules with each other. And save the Check Result to a Simple Dataset (i.e. Point, Line, Region Dataset) or CAD Dataset.

Function entrance

• Data tab-> Topology group-> Topology Check.

Operation steps

1. Click the Topology Check button to pop up the Topology Check dialog box;
2. Add the Dataset for the parameter Topology Check via Add button on the toolbar. The Dataset List will display the information of Dataset, Datasource, and Topology Rules. The details are as follows:
   • Dataset: Data set to be checked for Topology Check.
   • Datasource: Datasource of the Data set to be checked for Topology Check.
   • Topology Rules: check rules used when performing Topology Check on the Check Data set, 37 types in total. Topology Rules can be selected in the Topology Rules dialog box in the Parameter Settings area. See the Topology Check rule for a detailed description of Topology Rules.
3. After selecting a row of Dataset on the left, set the following Parameters:
   • Topology Rules: Rules used for Topology Check. The system will list all Topology Rules applicable to the Class Dataset according to the type of the Data set to be checked. After selecting a Topology Rule, the icon of the corresponding rule will be displayed in the "Rule Description" area on the right, which is convenient for the user to understand the selected Topology Rule more intuitively.
   • Tolerance: Tolerance value used for Topology Check and Topology Preprocessing, such as the distance between nodes. Different tolerance is required for different Topology Rules. It is recommended to use the default tolerance. Tolerance units are consistent with Dataset units. Tolerance defaults are related to the Dataset's coordinate system and are described in the tolerance description .
   • Filter Expression: The participating objects can be filtered by Filter Expression, so that the objects meeting the conditions can participate in Topology Check. See the SQL Statement Query for information on how to use SQL Expression.
   • Repair topology error: The system can automatically repair the errors detected by some Topology Rules. After selecting the Topology Rules that can be automatically repaired, the "Repair topology error" item will change from gray to checkable. When checked, you can repair the Check Data set at the same time as the Topology Check.

     The Topology Rules that can be repaired automatically are shown in the following table:

     Remove redundant nodes on Remo Deletes the overlapping portion of Snap all the nodes within the Adds a matching node Adds a point of intersection

     Topology Rules	Repair method
     No pseudo nodes in line	The false node is changed into a node, that is, the two lines connected by the false node are merged into one line.
     L/R has no redundant vertex	line or face boundaries.
     Line not overlap line	If the line object in the to-be-checked Data set overlaps with the line object in the Reference dataset, the overlapping part of the line object in the to-be-checked Data set will be deleted.
     No self overlap in line	ves the self-overlapping portion of the line object.
     No overlap in line	one of the line objects.
     Vertex distance > tolerance	tolerance range together, that is, combine them into one node.
     vertices must match	to the line object.
     Vertex exists at line intersect	at the intersection of two line segments.

4. Set up Reference Data, including Datasource and Dataset Information.
   • Datasource: The Datasource where the Reference dataset is located. The default is the Datasource where the Data set to be checked is located.
   • Dataset: Select a Reference dataset for Topology Check. Depending on the Topology Rules, some rules will use two Datasets for Topology Check. For example, "Point must on line" "requires a Line Dataset as the Reference dataset; Other rules only perform Topology Check in a Dataset, such as "No overlap in line", and only need to select the Data set to be checked.
5. Set the Result Data storage location to the name.
   • Datasource: The Datasource where the Result Dataset is located. The default value is the Datasource where the Data set to be checked is located.
   • Dataset: After selecting a Topology Check record in the list box, you can set the name of Result Dataset here. The default name is TopoCheckResult. The Result Dataset type is related to the Topology Rules set for the record.
   • Save to the same dataset.: If this item is checked, all the Topology Check results in the list box will be saved to the same Dataset (CAD Dataset). Dataset Name is the name displayed in the current Result Dataset. If this option is not checked, the user can set the name of Result Dataset for each Topology Check record in the list box.
6. Select the Auto Close when finished check box to Auto CloseValidate Topology the dialog box after Application completes the Topology Check of all records in the list box.
7. Selecting When finished, open the error checker will automatically open the Error Checker dialog box after completing the Topology Check.

Related topics

Topology overview

Topology Preprocessing

Error Checker

Topology Logic Diagram

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