Creating point cloud visualisations with OpenTopography
Land Information New Zealand has a partnership with OpenTopography allowing 3D point cloud data to be downloaded, processed and visualised. This partnership complements the publishing of DEM and DSM products on the LINZ Data Service.
High resolution topographic data is useful for scientific, environmental, engineering and planning purposes. OpenTopography facilitates access to data that can be technically challenging to work with. By following the steps below, you’ll be able to explore and analyse an area of 3D point cloud data from your web browser.
If you’d like to dive straight in, explore the Wellington point cloud browser visualisation we’ve created for examples in this story.
Step by step — creating your own visualisation
Here we will guide you through access to New Zealand LiDAR data using OpenTopography, and explore the features of the 3D point cloud browser visualisation.
- Open a web browser and type in opentopography.org in the search bar.
- Scroll over and click on the Data tab on the top right hand corner of the screen. In the scroll down menu, select Point Cloud.
- In the Point Cloud Data Distribution and Processing page, you can filter point clouds by location. Click on the Filter by Location option scroll down to the bottom, select New Zealand and click the Filter button.
- Select and click on the third option, Abel Tasman and Golden Bay, Tasman, New Zealand 2016. Here we are on the Dataset Overview page. We can find an overview of the dataset, select an area to download or process and also find URLs to the corresponding Digital Elevation and Surface Models on the LINZ Data Service.
- Scroll down to the map window. Click Select a Region on the top left hand corner of the window, and drag a box¹ over the area you want to investigate (you can also tick Usage Heat Map on the top right hand corner to see which areas have been looked at by other users).
- You can also manually enter your area of interest using NZTM coordinates using the Coordinates and Classification section below the map window. Once you have selected your area, you can scroll down to select which Return Classification(s) you want to download. You can also choose to download this point cloud data in LAS, compressed LAZ or in a readable ASCII format.
- Under 3D Point Cloud Visualisation, select the option to Generate 3D point cloud browser visualisation. This will generate a Potree web server allowing you to view and manipulate point cloud data. This option will be investigated in further detail below.
- At the bottom of the page under Job Description enter your email address to have the job sent to your email on completion and for future reference. Click Submit.
- You will now be redirected to the Point Cloud Job Report page, which might take a few minutes to process. You will then be given details about the job and links to various products as they are produced.
- Under 3D Point Cloud Visualisation, click View 3D point cloud in your browser. This will take you to the 3D point cloud browser visualisation in another tab.
Exploring the visualisations
The OpenTopography 3D point cloud browser visualisation has many different capabilities and options.
You can modify point cloud features such as size, colour and attributes, and analyse areas within the point clouds in different ways. To explore these features, click on the Menu button on the top left hand corner of the screen.
Here you can find several tabs that can be clicked and expanded:
Appearance
In the Appearance tab you can change the amount of points shown, point size, field of view and much more.
You can also change the types of features that are shown, for example in the GIF at the top of the page, unclassified, water and vegetation were turned off to show the bare earth points.
This can be done by firstly changing the display attribute to Classification from the default of RGB, under the Display attribute tab. Then click on the Classification filter tab and select which classifications you want to view.
Cross sections and measurements
Under the Tools tab there are many different measuring tools. You can calculate straight line distance from two selected points, measure areas and volumes as well as viewing cross sections.
To create a cross section click on the tool represented by a multicoloured line. Select two points on that map you want to view in a two dimensional cross-section, and then right click to finalise this selection.
Scroll down and click on the Measurements tab. You can change the width of the cross section and also the position of the graph by clicking and dragging one of the end points.
This cross section gives a great representation of elevation variation and distribution across the dataset.
Elevation
You can also change the symbology of the point cloud depending on elevation. This can be achieved by using the Elevation range slider under the Display attribute tab when Elevation is selected on the Attributes dropdown.
You can slide the bar to give the desired range and interval.
This is a brief overview of the capabilities of the OpenTopography point cloud platform and the 3D point cloud visualisations. Happy exploring!
Licensors and attribution
The LiDAR data used in this story is licensed by Tasman District Council and Wellington Regional Council for re-use under the Creative Commons Attribution 4.0 International license.
All of the New Zealand elevation data available on OpenTopography is available for free under the same license.
The licensor should be specified when attributing LiDAR Data. See Attributing elevation or aerial imagery data for more details.
- You can download up to 50 million points as a guest. To download more points, have an archive of your jobs, share job results and more, you can create your own OpenTopography account for free. Just scroll to the top of the page and click on MyOpenTopo, below the Login option, where you can find instructions to create your account.
