Lesson 10b1: Intro to LAS Files in ArcGIS Pro

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Detailed Description

The following series of lessons will cover how to use LiDAR data in the ArcGIS Pro environment. In this lesson, we will provide the user with an overview of how to load and view lidar files in the standard LAS format in both 2D and 3D.


Date Taken:

Length: 00:15:37

Location Taken: US


Lesson 10b1: Introduction to LAS Files in ArcGIS Pro. ArcGIS Pro is an Esri Geographic Information Systems (GIS) software package that can help manage GIS data, conduct analysis, and create maps to print or share online. The United States Geological Survey has an enterprise license with Esri that allows all employees to obtain a copy of the software. Because of the prevalence of the software in private industry, academia, and government, the following series of lessons will cover how to use lidar data in the ArcGIS Pro environment. In this lesson, we will provide the user with an overview of how to load and view lidar files in the standard LAS format in both 2D and 3D.

By the end of this lesson, you will load and view individual LAS files in ArcGIS Pro, change their symbology, and filter the data by classification values. Subsequent lessons will cover the basics of an LAS dataset, and more advanced features such as editing LAS class codes, fixing anomalies and misclassifications, exporting LAS point cloud data into derived raster surfaces, and creating basic 3D analysis products. If you’re interested in learning more about using USGS lidar data in other software packages, additional videos will show how to use lidar data in Global Mapper and LP360.

Before we begin, you will want to download some lidar data to use during our exercise. The National Map has a download client where you can find USGS products to include elevation data such as lidar point clouds at https://viewer.nationalmap.gov/basic/. If you are interested in learning more about downloading products on The National Map, be sure to check out our training videos located at: https://www.usgs.gov/core-science-systems/national-geospatial-program/training.

However, for this lesson, we’ve conveniently packaged six tiles of LAS data into a zip file called “USGS_LPC_CO_SoPlatteRiver_Data_for_Lessons.zip” and loaded it to our FTP site at: ftp://rockyftp.cr.usgs.gov/Training_Data/. Please navigate to this location and download the zip package. This may take approximately 15 minutes to download.

After you’ve downloaded the lidar data, extract the zip file into a folder on your local computer to use during the lesson.

You should have ArcGIS Pro loaded on your system. If you do not, and you work for USGS, you can download a copy of the latest version of the software on the USGS Enterprise GIS Support page. Work with your local IT team to install the software on your system. We are specifically using ArcGIS Pro 2.2 but any 2.X version should work.

We’ll now launch the software.

You can open ArcGIS Pro by clicking Start >> ArcGIS >> ArcGIS Pro.

ArcGIS Pro is fully integrated with ArcGIS Online, so you will need an account with your username and password. If you are a USGS employee and do not have one already, you can request one through the USGS EGIS team. Item 2 has a link for filling out a form to request an account.

If this is the first time you’ve launched ArcGIS Pro or you are currently signed out, you will see  a log-in window. Go ahead and type in your username and password and select Sign In.

Once you sign-in, or if you were already signed in, you will see the ArcGIS Pro home page. Under ‘Create a new project,’ click the Map.aptx icon.

ArcGIS Pro will prompt you to provide a project name and location. We’ll call our project ‘ArcGIS_Pro_Lidar_Training_Lesson_1.’ Pick any save location on your local machine. We will use the same folder we downloaded the lidar data to earlier in the lesson. Once you have typed in this information, click ‘OK’.

ArcGIS Pro should open a new map document with a ‘Topographic’ base map.

ArcGIS Pro is capable of loading and viewing LAS formatted lidar data. ArcGIS supports LAS versions 1.0, 1.1, 1.2, 1.3, and 1.4. We’ll now load one tile of LAS data into our ArcGIS Pro map frame.

Left-click the yellow ‘Add Data’ button under the ‘Map’ tab at the top of the view window. Browse to the location where you have the lidar data for this lesson. Select the first tile, ‘USGS_LPC_CO_SoPlatteRiver_Lot5_2013_13SDD480395_LAS_2015’ and click OK.

Your map display should zoom in on the one tile of lidar, in Apex Open Space Park just west of Golden, Colorado. The lidar tile will be outlined by a red box but will not show any lidar points until you zoom in closer. This is due to the display limit, which is set to a default value of 800,000 points. The map data frame should be in the default coordinate system of NAD 1983 UTM Zone 13N since that is what our point cloud tile is in. We will zoom-in so the points display. In the lower left of the main display window, change the scale to read 1:4,000 by typing the number in.

Your map now shows the lidar points in the LAS tile, color coded by elevation values, in meters. You can see the color values in the Table of Contents if you expand the LAS layer by clicking the triangle next to the imported LAS data tile. You will also see that only a small percentage of the points are currently being drawn on your screen.

ArcGIS Pro uses a context sensitive ribbon menu. So, you should only see tabs that are related to the data you are viewing. If you haven’t already, highlight the LAS file name in the Table of Contents click on the layer name. You will see an ‘LAS Dataset Layer’ section appear at the top of the view window with three tabs, ‘Appearance’, ‘Data’, and ‘Classification’.

In the ‘Appearance’ tab, click the ‘Symbology’ button and a ‘Symbology’ window will open on the right side of your screen.

In the new window, you should see that you are currently drawing points using ‘Elevation’ values from the point cloud. You have the option to draw the points using different values such as intensity or classification as long as the data has this information. You can also view the lidar data using contour lines, edges, and a surface either on their own or in combination with other layers. We’ll go ahead and view some of these options.

Uncheck the box under ‘Points’ to turn these off.

Click on the ‘Contours’ symbol and check ‘Draw contours.’ You can specify a contour interval by increasing or decreasing the point value. Here you can see the data displayed using contours.

Uncheck ‘Draw contours’ and click on the surface model symbol. Check ‘Draw using’ and keep the drop-down on ‘Elevation’. Here you can see the data using a surface model.

You’ll notice there were red artifacts when you displayed the contours and the surface model. These red artifacts represent noise points that are above the ground. They are red because they have high elevation values. Go ahead and turn off the ‘Draw using Elevation’ option under the Surface symbol. Click on the ‘Points’ symbol, check the ‘Draw using’ box, and select ‘Classification’ from the drop-down menu. You should see lidar points color-coded to match the classification type.

This lidar dataset shows three colors. Gray represents a classification value of 1, which is processed but unclassified or unassigned. Brown shows a classification value of 2, which is ground. And red characterizes a value of 7, which is low noise. You should see these values in the table of contents, under the ‘USGS_LPC_CO_SoPlatteRiver_Lot5’ layer. Other common classification values you may see include 3, 4, and 5 for low, medium and high vegetation, 6 for building, and 9 for water.

Due to the classification codes present in lidar, simple filters can be set to show only subsets of the data. If you don’t currently have it highlighted, select the ‘USGS_LPC_CO_SoPlatteRiver_Lot5’ layer in the Table of Contents. In the LAS Dataset Layer Ribbon menu, select the ‘Appearance’ tab. You should see a drop-down button called ‘LAS Points.’ Select ‘Ground’ from the drop-down list.

Only the brown points representing ground should be visible. Click on the Symbology window and turn off the Points display and turn on the Surface display.

You should notice that the elevation model looks much cleaner and the red artifacts are gone. Click the Save button in the upper left to save your work.

Up until now, we’ve been viewing the lidar data in 2D. The final part of this lesson will cover how to view lidar in 3D within ArcGIS Pro.

In ArcGIS Pro, a 3D map is called a scene. To view your lidar data in 3D, you must convert your map into a scene. On the ribbon menu, select the ‘View’ tab. Click the ‘Convert’ button and Global Scene. This will launch a global scene. However, we are interested in a Local Scene since our data is in a small area. Next to the ‘Convert’ button, click ‘Local.’ You may not see your data initially. Just right-click your imported LAS data tile layer and select ‘Zoom to Layer’ and you will zoom to your data.

On the ribbon menu, select the ‘Map’ tab. Click the ‘Explore’ button to activate the Explore tool. Your left mouse button will pan the map, your right mouse button will control a continuous zoom, and clicking and holding the mouse wheel will rotate and tilt the scene. Go ahead and zoom-in on your data so you are about 2,000 meters above the ground. The lower left of the map window has an area where you can type in 2,000.

ArcGIS Pro will let you overlay multiple symbology layers on the same lidar file. You are currently displaying the surface model. In the Table of Contents, activate the ‘USGS_LPC_CO_SoPlatteRiver_Lot5’ layer by clicking it. Select the ‘Symbology’ window, click on the ‘Contours’ button, and check ‘Draw contours.’ Set the contour interval to ’10’ to space out the lines.

Congratulations! You’ve finished Lesson 10b: An Intro to LAS Files in ArcGIS Pro. Click the ‘Save’ button and close out of ArcGIS Pro.

During this lesson, you learned how to load and view individual LAS files in ArcGIS Pro, change their symbology, and filter the data by classification values. You also displayed lidar LAS files in both 2D and 3D.