LiDAR

Goals:

The goal of this lab is to work with LiDAR data and be able to process and retrieve various surface terrain models. Also to create and process intensity images from point cloud data. Working with point clouds in LAS data formats is another goal of this lab.

Methods:

In this lab Erdas Imagine GIS techniques and ArcMap were utilized.

Part 1: Point Cloud Visualization in Erdas Imagine
In the first part of this lab we loaded LAS files of Eau Claire into Erdas Imagine. This was to check for any errors in the data. The next step was to look over the metadata. We then analyzed the same data set  in ArcMap and further manipulated the data in this program. (Figure 1)

 Figure 1. Eau Claire data in Erdas Imagine

Part 2: Generate a LAS Dataset and Explore LiDAR Point Clouds with ArcGIS

In this part of the lab we created a LAS dataset and explored the properties of this dataset. We then began applying visualization techniques to the LAS dataset and manipulated it as point cloud data. This was done in both 2D and 3D. We explored different ways to display the data and utilize the LAS Dataset toolbar in ArcMap. We then sorted the data by elevation and classification as well as applying a number of filters to change the view of the data. (Figure 2)

Figure 2. Eau Claire DSM (Digital Surface Model)

Part 3: Generation of LiDAR Derivative Products

In this section we worked with Digital Surface Models (DSM) with first return, Digital Terrain Models (DTM) and then added the Hillshade feature to both the DSM and the DTM.

We set the data points to be displayed by elevation and tested the filters (first return, ground and non-ground).  After we used the LAS to Raster tool set setting the type to maximum elevation and using the nearest neighbor method. After that we implemented the Hillshade filter. (Figure 3)

This process was then repeated with the ground filter to get a different elevation result. Hillshade was applied to this finished product as well. Next we created a LiDAR intensity image by using a very similar procedure as we had done previously. We set the LAS dataset to display elevation, specifically first returns. 
Using LAS to Raster again I produced an image that at first appeared dark in ArcMap until it was transfered as a tif file into Erdas. (Figure 4)

Results:

Figure 3. Hillshade feature 

Figure 4. Image intensity final product viewed in ArcMap Panchromatic image of Eau Claire

Sources

LiDAR point cloud data from Ayres Associates of Eau Claire County from 2013. 

point clouds

in LAS file f