Oct. 17-18, 2009Oct. 17-18, 2009

Tutorial 1– Visualization of Point Cloud DataTutorial 1– Visualization of Point Cloud Data

Introduction to the Acquisition, Visualization and Interpretation of lidar-derived Digital Elevation Models.Introduction to the Acquisition, Visualization and Interpretation of lidar-derived Digital Elevation Models.

1. Load Points and Reference image

2. View points colored by elevation

3. View points colored by intensity, return, number

4. Add surface, ortho to viewer

5. View points colored by classification

6. View points colored by ortho

DOGAMI lidar data sample from Carpenterville on Southern Oregon Coast. 8 pulse/m2 leaf-on points in LAS format, 14,000,000 points in 1.4 km2 tile

Fusion is a free lidar point data viewer produced by the USDA Forest Service, and available for download at http://forsys.cfr.washington.edu/fusion/fusion270.html

Oct. 17-18, 2009Oct. 17-18, 2009

Tutorial 1– Visualization of Point Cloud DataTutorial 1– Visualization of Point Cloud Data

Introduction to the Acquisition, Visualization and Interpretation of lidar-derived Digital Elevation Models.Introduction to the Acquisition, Visualization and Interpretation of lidar-derived Digital Elevation Models.

Load points and Load points and reference imagereference image

• Launch Fusion• Load data from LAS file

42124B3317• Load Image

42124b3317_ortho• Select Tools>

Miscellaneous Utilities> Examine LAS file headers

• Note number of points, ratio of returns, lack of projection info

• If no image is available, use Tools> Miscellaneous Utilities> Create an image using lidar point file

• Select LAS file for input, select output name

• Select Clamp data range and run

Oct. 17-18, 2009Oct. 17-18, 2009

Tutorial 1– Visualization of Point Cloud DataTutorial 1– Visualization of Point Cloud Data

Introduction to the Acquisition, Visualization and Interpretation of lidar-derived Digital Elevation Models.Introduction to the Acquisition, Visualization and Interpretation of lidar-derived Digital Elevation Models.

• In Sample options, choose color by height, all returns, stroked box

• Draw selection box on image• Initial display will be slow while

Fusion indexes data• LDV viewer will pop up with image• Experiment with navigation, mouse

to rotate view, ctrl and mouse to zoom

• Right click on screen to bring up menu, select spinning side view or wiggle vision

View points by elevation

Oct. 17-18, 2009Oct. 17-18, 2009

Tutorial 1– Visualization of Point Cloud DataTutorial 1– Visualization of Point Cloud Data

Introduction to the Acquisition, Visualization and Interpretation of lidar-derived Digital Elevation Models.Introduction to the Acquisition, Visualization and Interpretation of lidar-derived Digital Elevation Models.

View points colored by intensity, return, number

• In Sample options, choose color by intensity, all returns, stroked box

• Draw selection box on image

• Note that intensity values are not normalized

• Return to sample options switch to color by return

• Note the ratio of first to second and third returns

• Return to sample options, switch to color by pulse number

• This visually sorts pulses from adjacent swaths

Oct. 17-18, 2009Oct. 17-18, 2009

Tutorial 1– Visualization of Point Cloud DataTutorial 1– Visualization of Point Cloud Data

Introduction to the Acquisition, Visualization and Interpretation of lidar-derived Digital Elevation Models.Introduction to the Acquisition, Visualization and Interpretation of lidar-derived Digital Elevation Models.

Add surface, ortho to viewer

• In Sample options, choose color by height

• Draw selection box on image

• Right click on screen in LDV, click on ortho image, select 42124b3317_int to load intensity image which is a 1.5 ft pixel raster made from the first returns intensity values

• Right click in LDV again and click on image plate

• Use I/i to raise and lower image through points.

• Spacebar to bring up menu, click on surface file, choose be3317_dem.dtm

• Play with image• Make the DTM using

Tools> Terrain Model> Import ESRI ASCII raster file

Oct. 17-18, 2009Oct. 17-18, 2009

Tutorial 1– Visualization of Point Cloud DataTutorial 1– Visualization of Point Cloud Data

Introduction to the Acquisition, Visualization and Interpretation of lidar-derived Digital Elevation Models.Introduction to the Acquisition, Visualization and Interpretation of lidar-derived Digital Elevation Models.

View points colored by

classification• In Sample options,

choose color using LAS classification, choose truncate attribute range, set minimum = 1, maximum = 2, set start color to white

• Draw selection box on image, examine point cloud

• Right click on screen in LDV, click on colors, set background color to white

• Image will now display only ground points

Oct. 17-18, 2009Oct. 17-18, 2009

Tutorial 1– Visualization of Point Cloud DataTutorial 1– Visualization of Point Cloud Data

Introduction to the Acquisition, Visualization and Interpretation of lidar-derived Digital Elevation Models.Introduction to the Acquisition, Visualization and Interpretation of lidar-derived Digital Elevation Models.

View points colored by

image• In Sample options,

choose color using image

• Draw selection box on image, examine point cloud

• Points are now colored with values from corresponding location in ortho_image

• Use ctrl +/- to change point size