Lesson 1: Visualize 3DEP Lidar Data with uniDEM
This tutorial illustrates methods to load, view and interact with 3D point clouds and will cover the following topics.
Load lidar points
Display lidar points
Interact with the 3D data view
View individual point classifications
Profile lidar point classifications in LAZ files
Turn on/off lidar point Classes in 3D views
Change lidar point colors
The sample data used in this lesson is 3DEP lidar data in two LAZ files in LAS version 1.2 and located in Madison, MS, USA.
Prior to commencing this lesson, please perform the following:
Download Sample Data: Madison (size: 37 MB)
Unzip the contents to a working folder
This lesson will take approximately 20 minutes.
The following video executes the steps in the tutorial.
VIDEO
1. Install and Open uniDEM
Install uni DEM using one of two options:
Open uniDEM
Help references:
Window Overview
2. Load Lidar Point Clouds
Click uniDEM icon
Click Load LIDAR
Open the unzipped working data folder
Select both LAZ files
Click Open
Click OK to maintain LAS v1.2
Click Yes to all files into single dataset
Enter Madison for the combined dataset name
Data is displayed in the Table Of Contents (TOC)
Help references:
Load LIDAR |
Data Management |
Table of Contents
3. Display Lidar Point Cloud
Display Both LAZ Files
Right Click Madison in the TOC
Click Check All
Initial Lidar Point Display
Lidar points for both files are displayed top down (2D)
Points are colored based on the LAS classification in the point metadata
Notes:
Points density and display size are set conservatively by default (see next step)
If no Class exists points are colored by elevation
Set Point Size and Density
Click the LIDAR tab
Click the Point Size dropdown and set to large.
Click the Density dropdown to render more or less points
Note: Increasing density reduces render rates
uniDEM strides lidar points for rendering performance.
Help references:
Table of Contents |
Point Density |
Point Size
4. Interact with 3D view
Click into data view
Rotate: Right click and move mouse left or right
Tilt Right click and move mouse up or down
Move: Left click and move mouse in any direction
Zoom: Scroll wheel mouse forward/backward
Toggle 2D/3D: Press key 2 and 3
Help references:
Data Views |
2D/3D Display
5. View Lidar Point Detail
Place the cursor is placed over a lidar point to see point details above the cursor and in the TOC.
Lidar class is displayed over cursor
Elevation (Z)is displayed over cursor
Source Lidar file is displayed in TOC
Lidar Class is displayed in TOC
LAS metadata including:
Edge of Flight
Intensity
Keypoint
Point Source ID
Return
Scan Angle Rank
Scan Direction
Synthetic
Time
User Data
Withheld
Overlap (LAS v1.4)
Help references:
Table of Contents |
Data Views
6. LAS Class Profile
Profile Entire Dataset
Click LIDAR tab
Click Class Profile button
Click OK to use the Madison dataset
Click Select All to select both LAZ files
Click OK
The dialog presents the following information:
Total number of points
Each LAS Class type in the selected datasets
The count for each LAS class
Note: This project contains misclassifications, for example buildings are classified as Medium Vegetation (4) and Overlap
as Reserved For ASPRS (11).
Profile Selected Area
Press r on keyboard to enable rectangle drawing tool
Hold Shift + Left click while moving mouse to draw a rectangle
Click Class Profile button
Click OK to use the Madison dataset
Click Select All to select both LAZ files
Click OK
The dialog presents the following information for only points within the rectangle:
Total number of points
Each LAS Class type in the selected datasets
The count for each LAS class
Note: This project contains misclassifications, for example buildings are classified as Medium Vegetation (4) and Overlap
as Reserved For ASPRS (11).
Help references:
Class Profile |
Rectangle Drawing Tool
7. Turn On/Off Lidar Points by Class
Click LIDAR tab
Click Show/Hide Classes button
Click Ground (2) in the selection dialog
Hold Ctrl and click Water (9) in the selection dialog
Click OK
The view turns off all lidar points that are not of class Ground(2) or Water (9).
Notes:
The remaining points are remain loaded, but not visible
Independent data views can present different classes
Help references:
Show/Hide Classes
8. Change Lidar Point Colors
Color By Elevation
Within the LIDAR tab
Click Color button
Select Color By Elevation
Click OK to use the Madison dataset
Click Select All to use both LAZ files
Click OK
Click OK to select the Jet color scheme
Click OK to select Auto color scale
Click OK to use 1 as the lowest percentile
Click OK to use 99 as the lowest percentile
Color By Intensity
Within the LIDAR tab
Click Color button
Select Color By Intensity
Click OK to use the Madison dataset
Click Select All to use both LAZ files
Click OK
Select Gray from the drop down in the color scheme dialog
Click OK to select Auto color scale
Click OK to use 1 as the lowest percentile
Click OK to use 99 as the lowest percentile
Help references:
Lidar Point Color