Introduction ¶

The article opens by noting that “Google Maps, Google Earth, Uber are examples leading software/apps that are driven by GIS,” demonstrating how geospatial technology has become ubiquitous. The author emphasizes that these platforms have made GIS accessible to non-experts, allowing people to appreciate its capabilities through Google Earth.

Problem Context ¶

During an “Introduction to QGIS” course, a client submitted a dataset created in Google Earth. However, GIS experts repeatedly rejected the data, citing unspecified errors. The client struggled to understand what was wrong with their dataset.

Solution Methodology ¶

The author identified topology errors and documented the debugging process in systematic steps:

1. Data Import & Conversion ¶

Load KML into QGIS, then convert to Geopackage, spatialite, or shapefile due to limited KML editing capabilities

2. Data Inspection ¶

Examine layer attributes and identify duplicates using layer styling visualization options

3. Topology Checker Activation ¶

Configure rules to report errors using the Topology Checker plugin

4. Handle Null Geometries ¶

Address null geometries preventing checker execution; use expressions to select and delete problematic records

5. Identify Gaps ¶

Employ Minimum Bounding Geometry algorithm, run difference calculations, and symbolize results to visually highlight gaps

6. Error Resolution ¶

Execute “Delete Duplicate Geometries” algorithm, activate snapping, manually correct errors, or apply the v.clean processing algorithm

Conclusion ¶

The author demonstrates a practical workflow for explaining topology concepts to non-GIS professionals, translating technical errors into understandable visual representations.