Point Cloud Processing and 3D Visualization with QGIS

In this lecture you learn the definition of point cloud data. You'll also learn how the data are acquired and used. Finally, you'll learn about the Point Data Abstraction Library (PDAL).

This lecture gives an overview of point cloud data sources. Find community resources on OpenTopography, check with your national mapping agency or find remote data sources that you can stream to QGIS.

In this practical session you'll download four LAZ tiles for the city of Rotterdam, that we'll use as a case study. The tiles are: 37FZ1_23, 37FZ1_24, 37HN_03 and37HN_04. Next, you'll load the tiles into QGIS, where it automatically processes the LAZ to COPC format. In the end you'll have the center of Rotterdam in true color on your screen.

In this practical session, you learn how to check the properties of the point cloud tiles using the Information tool that you can find in the QGIS Processing Toolbox under Point cloud data management.

This lecture explains the Virtual Point Cloud (VPC) format that is useful for processing and visualization of large datasets with many point cloud tiles.

In this practical session, you'll use QGIS to merge the four LAZ tiles into a Virtual Point Cloud (VPC) layer that you can use for further processing.

Our study area is smaller than the area covered by the downloaded tiles. In this practical session we're going to clip the VPC layer to a polygon shapefile.

The clipped point cloud layer from the previous practical session is in the VPC format and in QGIS we can only see its extent. This is useful for intermediate data that we would like to further process. However, if we want to visualize this intermediate result, we need to convert it to a COPC layer. That's what you'll learn in this practical session.

You might have noticed that in the result of the previous practical session the projection information got lost in the created COPC layer. In this practical session you'll learn how to assign a projection to a point cloud layer.

In this lecture you'll learn the theory of point cloud interpolation algorithms available in QGIS. We'll covert the differences between DSM and DTMs and explain the IDW and TIN interpolation algorithms.

This lecture introduces this section.

In this practical session, you learn how to create Map Themes in QGIS. Map Themes are presets of layers in the Layers panel that can be quickly visualized. Map Themes can be used in the 2D, 3D view and Print Layout. We'll use the result in the next practical session.

In this practical session, you'll compare layers in two 2D map views that are synchronized.

In this practical session, you'll learn how to use the Elevation Profile tool of QGIS.

In this practical session, you'll learn how to use the QGIS 3D view and create amazing 3D visualisation.

Introduction to this section.

Before you'll filter point cloud data, it's important to check the statistics of the attributes. This practical session will guide you through the process.

In this practical session, you'll learn how to filter point cloud data using the classification attribute. You'll use it to filter buildings.

In this practical session, you'll go a step further and filter point clouds with expressions. You'll refine the expression to improve filtering of trees.

Until now, you've used filters as a separate process. Filters, however, are also included in some point cloud processing tools. While using these tools you can define an extent and a filter under the advanced section in the dialog window. The tool will then be applied to these points.

In this section, we'll use PDAL wrench to automate point cloud processing. Before we can use the PDAL wrench commands, we need to set it up. You'll learn that in this practical session.

In this practical session, you'll learn to create a VPC from 4 LAZ tiles. You'll use the VPC in the next session.

In this practical session, you'll clip the VPC from the previous session using the boundary polygon (shapefile) that we've used in Section 3.

In this practical session, you'll interpolate the clipped VPC layer from the previous session using IDW. The result is a DSM in GeoTIFF format that you can visualize in QGIS.

Besides using VPC files, you can also apply PDAL wrench commands to LAS or LAZ files. Here you'll learn how to merge the 4 LAZ tiles into one large LAZ file.

In this practical session, you'll use the same Clip command as in Lecture 28, but now applied to a LAZ file.

In this session, you'll learn how to use PDAL wrench for filtering point cloud data. We'll use the same filter as used in Lecture 24.

In this practical session, you'll create a batch file that automatically creates a VPC from 4 LAZ tiles, clips it to a polygon and interpolates it using IDW.