Is there a way to build topology and work with topology relations in PyQGIS?

How to build topology in QGIS?

QGIS has a built-in topological editing feature, which is great for creating new features without errors. But existing data errors and user-induced errors are hard to find. This plugin helps you find such errors through a list of rules. It is very simple to create topology rules with the Topology Checker plugin.

What is topology rules in Qgis?

Topology expresses the spatial relationships between connecting or adjacent vector features (points, polylines and polygons) in a GIS. Topological or topology-based data are useful for detecting and correcting digitising errors (e.g. two lines in a roads vector layer that do not meet perfectly at an intersection).

Does QGIS have a built in topological editing feature?

Enable topological editing is for editing and maintaining common boundaries in features mosaics. QGIS ‘detects’ shared boundary by the features, so you only have to move a common vertex/segment once, and QGIS will take care of updating the neighboring features.

Can a shapefile have topology?

A shapefile is a nontopological data structure that does not explicitly store topological relationships. However, unlike other simple graphic data structures, shapefile polygons are represented by one or more rings.

What are 7 types of topology?

Here’s an overview of each of these seven network topology types to help you get started:

• Point-to-point network topology. Point-to-point network topology is the simplest method.
• Bus network topology.
• Ring network topology.
• Star network topology.
• Mesh network topology.
• Tree network topology.
• Hybrid network topology.

How do I fix topology in QGIS?

Clean Topology Error in Polygon Data set

1. Open v. clean.
2. To clean the error, there are three processes are needed to be done: break polygon, remove duplicate and remove area.
3. In the third step we must define threshold value.
4. Leave the other parameter as default.
5. Click Run button to start cleaning.

What are the three types of topology GIS?

In a GIS , spatial relationships among features are defined by topology.

• In a geodatabase, you can choose whether to create topology for features.
• There are three types of topology available in the geodatabase: geodatabase topology, map topology, and the topology created for a geometric network.

How do you create a topology map?

Creating a map topology

1. Click Select Topology. on the Topology toolbar.
2. Check the layers that will participate in the map topology.
3. Optionally, click Options to view the cluster tolerance, which is the distance that defines how close together edges and vertices must be to be considered coincident.
4. Click OK.

How to create topology?

Create a topology using the Create Topology wizard

1. In the Catalog pane, right-click the feature dataset to which you want to add a topology and click New > Create Topology.
2. Name the new topology and specify the cluster tolerance.
3. Check the boxes of the feature classes that will participate in the topology.

How do I fix topology in QGIS?

Clean Topology Error in Polygon Data set

1. Open v. clean.
2. To clean the error, there are three processes are needed to be done: break polygon, remove duplicate and remove area.
3. In the third step we must define threshold value.
4. Leave the other parameter as default.
5. Click Run button to start cleaning.