validate topology

Function Description

Used to check objects that do not conform to topology rules in point, line, region datasets themselves and between different types of datasets, and save the check results to simple datasets (i.e., point, line, region datasets) or CAD datasets.

Function Entry

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

Operation Steps

  1. Click the Validate Topology button to pop up the Validate Topology dialog;
  2. Through the Add button on the toolbar, add datasets participating in Validate Topology. Two methods are provided: Add a rule and Batch Add:
    • Add a rule: Add one dataset at a time.
      • If the current rule list is empty, automatically add the first vector dataset in the first data source of the current workspace.
      • If the current rule list already contains datasets to be checked, add the last dataset in the list again.
    • Batch Add: Open the selection dialog to select multiple datasets simultaneously.
  3. The dataset list will display Dataset, Datasource, and Topology Rules Information. When a record row is selected, you can switch the data source and dataset to be checked in the dropdown menu. Read-only data sources are not supported for Validate Topology; the program will automatically filter out read-only data sources in the current workspace.
    • Dataset: The dataset to be checked that requires Validate Topology.
    • Datasource: The data source where the dataset to be checked that requires Validate Topology is located.
    • Topology Rules : The inspection rules used when performing Validate Topology on the dataset to be checked, totaling 37 types. Topology rules can be selected in the Topology Rules dialog within the parameters area. For detailed descriptions of topology rules, please refer to Validate Topology Rules.
  4. After selecting a dataset row on the left, set the following parameters:
    • Topology Rules : Rules used for Validate Topology. The system will automatically filter topology rules suitable for this class dataset based on the type of the dataset to be checked.
      • If the set topology rules are duplicated (same dataset, same rule), a prompt box will pop up indicating that the rule already exists.For example: The 'no identical points' topology rule for dataset "CityA_P" already exists.
      • After selecting a topology rule, an illustration of the corresponding rule will be displayed in the "Rule Description" area on the right, making it easier for users to intuitively understand the selected topology rule.
    • Tolerances: Tolerances used for Validate Topology and topology preprocessing, such as the distance between nodes. Different topology rules require different tolerances; it is recommended to use default tolerances. The tolerance unit is consistent with the dataset unit. The default tolerance value is related to the dataset's coordinate system; for specific descriptions, please refer to Tolerance Description.
    • Filter Expression: You can filter participating objects using filter expression, so that only objects meeting the conditions participate in Validate Topology. For how to use SQL Expression, please refer to SQL Expression.
    • Repair topology error: The system can automatically repair errors detected by some topology rules. After selecting topology rules that can be automatically repaired, the "repair topology error" item will change from gray to checkable. After checking this item, the dataset to be checked can be repaired while performing Validate Topology.

      Among them, topology rules that can be automatically repaired are listed in the table below:

      Topology Rules Repair Method
      no pseudo nodes in line Convert pseudo nodes to nodes, i.e., merge the two lines connected by a pseudo node into one line.
      l/r has no redundant vertex Delete redundant vertices on lines or region boundaries.
      line not overlap line If a line object in the dataset to be checked overlaps with a line object in the reference dataset, delete the overlapping part of that line object in the dataset to be checked.
      no self overlap in line Delete the self-overlapping part of the line object.
      no overlap in line Delete the overlapping part of one of the line objects.
      vertex distance > tolerance Snap all nodes within the tolerance range together, i.e., merge them into a single node.
      vertices must match Add matching vertices on line objects.
      vertex exists at line intersect Add intersection points where two line segments intersect.
      no overlap in region Delete the overlapping part of one of the regions.
      no identical points Randomly retain one of the points at the same spatial location.
  5. Set reference data, including data source and dataset information.
    • Datasource: The data source where the reference dataset is located, defaulting to the data source of the dataset to be checked.
    • Dataset: Select the reference dataset for Validate Topology. Depending on the topology rules, some rules use two datasets for Validate Topology, such as "point must on line", which requires a line dataset as the reference dataset; while other rules only perform Validate Topology within a single dataset, such as "no overlap in line", where only the dataset to be checked needs to be selected.
  6. Set the storage location and name for result data.
    • Datasource: The data source where the result dataset is located, defaulting to the data source of the dataset to be checked.
    • Dataset: After selecting a Validate Topology record in the list box, you can set the name of the result dataset here; the default name is TopoCheckResult. The type of result dataset depends on the topology rules set for that record.
    • Save to the same dataset.: If this option is checked, all Validate Topology results in the list box will be saved to the same dataset (CAD dataset), and the dataset name is the one displayed in the current result dataset. If not checked, users can set the result dataset name for each Validate Topology record in the list box separately.
  7. Check the Auto Close when finished checkbox; after the application completes Validate Topology for all records in the list box, the Validate Topology dialog will automatically close.
  8. Check When finished, open the error checker; after completing Validate Topology, the Error Inspector dialog will automatically open.
Notes:

If there are self-intersecting region objects in the data to be checked, it is impossible to perform the No gaps in region rule check on that region. It is recommended that when performing the No gaps in region rule check, first perform the no self-overlap in region rule check, or manually process the self-intersecting regions, and then perform the No gaps in region rule check.

Related Topics

Topology Overview

Topology Preprocessing

Error Inspector