Show Tokyo's 23-Ward Point Cloud Data in QGIS

Introduction

On October 31, 2024, the Tokyo Metropolitan Government released high-precision 3D point cloud data for the 23 wards as part of its Digital Twin Realization Project, which aims for a Smart Tokyo. The data is expected to be used for disaster prevention and urban planning simulations, as well as in tourism and gaming.

This article explains an overview of the Digital Twin Realization Project, the data that has been released, and how to use it in QGIS.

What is the Digital Twin Realization Project?

The Tokyo Metropolitan Government's Digital Twin Realization Project is an initiative to recreate various elements of physical space in cyberspace and build a digital space that is linked to reality like a twin. The Tokyo Metropolitan Government aims to use digital twins to solve future challenges and improve the lives of Tokyo residents, with a goal of realizing this by 2030.

The project collects and analyzes data in real time using sensors and communication technologies, and it is expected to help with urban development, disaster prevention, and the environment. Through collaboration among industry, academia, and government, it is building a platform for centralized management and use of geospatial data and putting it into practice in many fields.

The Digital Twin Realization Project website offers the “Tokyo Digital Twin 3D Viewer,” which visualizes the cityscape of Tokyo in 3D. In addition to the point cloud data released this time, you can overlay many other kinds of data, such as 3D city models, on the 3D map.

Released data

The release includes not only point cloud data but also DEM data, orthoimages, and red relief image maps, and all of the data can be used in GIS. The data can be reused for any purpose, including commercial, academic, and personal use.

For details on the released data, see “(Attachment) Data Released as Open Data,” published by the Tokyo Metropolitan Government.

Using the data in QGIS

The released data can also be visualized easily in QGIS. This section displays the point cloud data in QGIS.

Downloading the point cloud data

To download the data, go to the “Tokyo Digital Twin Realization Project: Point Cloud Data of the 23 Wards” page on the G-Spatial Information Center.

Select Original Data (DSM) and Ground Data (DEM) (オリジナルデータ（DSM）及びグラウンドデータ（DEM）).

The areas available for download appear on the map as a grid. Click a grid cell to select it. This example selects the grid cell that contains Tokyo Station (09LD1874).

When the selection is done, click the download button on the left of the screen to start the download.

Adding the point cloud data to QGIS

Unzip the downloaded data and add it to QGIS by dragging and dropping.

The data appears as a red frame showing the extent of the point cloud. The first time QGIS loads LAS/LAZ data, it starts converting the data to the EPT (Entwine Point Tile) format, so it takes a little while for the data to appear. You can check the progress in the status bar at the bottom of the window.

When the processing finishes, data that looks like an aerial photograph appears on the map.

Displaying the data in a 3D map view

Now display the added point cloud data in a 3D map view.

From the menu bar, click View → 3D Map Views → New 3D Map View.

The 3D map view opens.

Use the controller at the top right of the screen to change the displayed area and the viewing angle. Alternatively, drag on the map to change the displayed area, or hold Ctrl while dragging to change the viewing angle. Scroll the mouse wheel to zoom in and out.

Looking at the area around Tokyo Station this way shows that the data captures fine details, from the shape of each building to features such as cars and the white lines on roads. Because this point cloud data was generated by laser scanner surveys from aircraft and similar platforms, the sides of buildings are not captured well.

Setting the symbology

When you add point cloud data, QGIS colors it by its RGB values, but you can also set the symbology you prefer in the layer properties.

Open the layer properties and select 3D View from the tabs on the left. From the drop-down at the top, select Attribute by Ramp, and for the attribute, select Z, which holds the elevation values.

In the 3D map view, the point cloud is now colored by Z value (elevation).

This article displayed point cloud data and changed its symbology in QGIS, but many other kinds of processing are possible. To learn more about processing point cloud data in QGIS, see the following article.

Adding DEM data and a red relief image map

Besides the point cloud data, the release includes other data such as DEM data. This section visualizes some of that data in QGIS.

DEM data

This example displays the “Grid data DEM (0.25 m)” data for the area around Shibuya Station in QGIS. The symbology gets redder as elevation rises and bluer as it falls.

The terrain clearly forms a valley toward Shibuya Station.

Red relief image map

The area centered on the Setagaya Castle Ruins in Setagaya ward, Tokyo, is displayed with “Micro-topography map (red relief image map) DEM (ground) (0.25 m).” The red relief image map visually emphasizes terrain relief and subtle differences in height, and it shows that the terrain around the Setagaya Castle Ruins changes sharply.

Near Setagaya Castle Ruins Park at the lower right in particular, historical terrain features remain, such as the remains of the castle moat.

Conclusion

This article covered the basics of displaying point cloud data in QGIS, as well as setting up the 3D map view and the symbology. With QGIS, you can visually manage and use not only this point cloud data but also many other kinds of geospatial data.