Manual LAS Classification: Reclassifying LIDAR Points by Freehand Selection on an Active Classification

In GIS and related fields, ensuring the accuracy of LiDAR data is crucial for further analysis and processing. To achieve the best terrain representation, users often need to adjust their datasets to fit specific requirements or types of analysis. This might involve isolating building points or distinguishing vegetation (such as high vegetation) from other objects like buildings. Manual reclassification becomes essential when automatic classification algorithms struggle to differentiate between similar features—like vegetation and low-lying structures. While automatic classification is a highly valuable tool, it can sometimes falter in complex or heterogeneous landscapes. In these situations, the ability to manually reclassify points provides users with greater control over their data, allowing them to refine it as needed for better accuracy. This makes freehand LAS classification an indispensable feature for professionals who require high-quality, precise spatial data. With SGIS v.R, users can easily draw freehand polygons on the graphics panel to select specific points. Once selected, the LiDAR toolbox can then be used to reclassify those points into a different category. Let's walk through an example to see how this feature works.