Viewing a profile with LASEdit
It can be useful to view a vertical slice through a LiDAR point cloud. You can see the cross-section of the landscape, and use that to help make mapping decisions.
House
I’ll use a house and its surrounds as an example. LASEdit can complain if the LiDAR data file is too large, so I’ll make a very small LiDAR file that only contains the area of interest.
Here’s the command to extract the small file (see other articles in this series if you want to know more):
las2las -i ACT2015_8ppm-C3-AHD_6886096_55_0002_0002.las -o HouseBushland12.las -set_version 1.2 -keep_xy 689365 6097310 689392 6097400
The output is a small .las
file:
01/04/2017 11:19 AM 1,042,087 HouseBushland12.las
Here are the steps to view a profile:
- Open the file in LASEdit.
- LASEdit asked about the elevation units: select metres.
- You see a top view of the terrain, with the LiDAR point cloud coloured according to elevation.
- Select the Profile tool on the left toolbar.
- Left-click a point to start the profile slice. Right-click the slice end point.
- LASEdit asks how wide the slice out to be. Values of 3 or 4 metres work well.
- A profile view appears.
Move the slice around by using the mouse wheel.
Here’s a link to the LiDAR data file for the house example. (Please respect the creative commons license applicable to ACT Government LiDAR data).
Road cutting
This example includes a road cutting. It was produced in a similar way to the house example. Notice that there is a 3D view of the terrain too. Use LASEdit’s 3D tool on the left toolbar to access it.
Here’s a link to the LiDAR data file for the road cutting example. (Please respect the creative commons license applicable to ACT Government LiDAR data).
Car park
The lowest (bluest) corner of the example above is a car park. You can see the cars there if you look closely. Here’s a profile of the car park in LASEdit.
Cairn
There is a rock cairn on the top of one of the hills in Gossan Hill Nature Park. Here it is.
Here’s the cairn in profile in LASEdit.
3D Views
LASEdit’s 3D view is fun to play with. In this view of the LiDAR data from a hospital campus, you can see a construction crane. It is coloured white, and it is in the upper middle part of the frame.
This article is part of the Orienteering Mapping with LiDAR, Smartphones and Free Tools series.
Polite and constructive responses are always welcome.