Neetmaps plugin training: – Qgis2threejs

Visualising 3d data in QGIS with the Qgis2threejs plugin

Introduction:

LiDAR data contains information about height as well as position and has become much more widely available in recent years. The Qgis2threejs plugin makes it quick and easy to visualise 3d data in qgis. Download the and install the plugin from the QGIS repository (type “3d” in the search box).

This is what we are aiming for!

©NERC (Centre for Ecology & Hydrology; British Antarctic Survey; British Geological Survey)

This particular example is based on the Tellus South West LiDAR dataset which was captured in 2013 and covers an area starting west of Exmouth and the whole of Cornwall. We will work with the LiDAR tile called dsm_ss64ne_5x5km.asc and take you through all the required steps to produce a 3d view like the one above.

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Neetmaps plugin training: – Qgis2threejs

About the data, what is Tellus South West?

The Tellus South West project is a collaborative, environmental survey and research project funded by the Natural Environment Research Council (NERC) and carried out by a partnership of the British Geological Survey (BGS), the Centre for Ecology and Hydrology (CEH), the BritishAntarctic Survey (BAS) and the University of Exeter Camborne School of Mines.

Find out more at http://www.tellusgb.ac.uk/

Lets make a start....

Step 1. Start QGIS and drag and drop the file dsm_ss64ne_5x5km.asc onto the map canvas. The DSM files contain all the features on the Earth's surface such as trees and buildings.

Note: You may get a warning about the CRS being undefined. Don't let this put you off as QGIS should have been configured to default to EPSG:27700 which is the British National Grid and is the correct map projection for this data.

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Neetmaps plugin training: – Qgis2threejs

You should see a greyish layer on the map canvas and the layer control should look like the screen shot below.

Step 2. Next, choose the Raster menu and select Terrain Analysis > Relief

Step 3. Complete the following dialog choosing a suitable name for the output layer. I havecalled it dsm_ss64ne_Relief. Leave all other values set to their defaults (we will create Relief colours in the next section).

We will use the newly created relief layer to place on top of the dsm (you can play around with various transparencies, 50% seems to work well).

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Neetmaps plugin training: – Qgis2threejs

The LiDAR data is beginning to take shape now but the DSM can be enhanced by changing the following layer properties....

Step 4. Go to Layer Properties (of the DSM) and Style and choose the following options.

Now press Classify and OK.

Step 5. Click and drag the DSM layer underneath the Relief layer if it's not already.

View the data in 3d using the Qgis2threejs plugin....

The plugin creates an html page which includes the controls and stores all the data in a javascript file.

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Neetmaps plugin training: – Qgis2threejs

Step 6. Make sure your options are kept as the defaults and check your dsm layer is selected as shown and press OK

Your output should now open in a browser and look like this.....

©NERC (Centre for Ecology & Hydrology; British Antarctic Survey; British Geological Survey)

The vertical exaggeration is set to 1.5 by default but it can easily be changed under the World menu. You will need to re-run the process for the changes to take effect.

Step 7. Open the custom plane controls and set a Plane Height of 1.0 and set the colour of the custom plane (dark blue or grey looks good). Your final output should look similar to the image below.

©NERC (Centre for Ecology & Hydrology; British Antarctic Survey; British Geological Survey)

If you have time, experiment with different settings or perhaps add another layer to the map canvas before using the 3d plugin. The image below is has been created in the sameway but has had Rights of Way overlain.

©NERC (Centre for Ecology & Hydrology; British Antarctic Survey; British Geological Survey)

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Neetmaps plugin training: – Qgis2threejs

Try experimenting with different resolutions and resampling settings. If you push the resampling to its highest setting and choose a resolution of 400% you will get some really impressive results.

Be warned though, this can lead to big files and processing times!

Further ideas...

You could also add a point layer and use that to visualise on the 3d surface. This could simulate a proposed Wind Turbine development or new Power line.

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Neetmaps plugin training: – Qgis2threejs

©NERC (Centre for Ecology & Hydrology; British Antarctic Survey; British Geological Survey)

For more information on QGIS migration and training, plugins or general GIS queriescontact:

email: info@neetmaps.co.ukwebsite: www.neetmaps.co.uk

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