Converting LiDAR data to raster (DEM/DSM) for ArcGIS input?

Question

I was wondering if there is an option to convert LiDAR data (.las) to a raster/grid (DEM/DSM) format that ArcGIS 10.0 can read?

Answer 1

The current option to import las files in ArcGIS is the LAS dataset data type. According to ESRI:

The LAS dataset provides fast access to large volumes of lidar and surface data without the need for data conversion.

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If the surface (raster) you are trying to create is a bare-earth DEM refer to the following posts:

One option is the LAS dataset to Raster tool, but only when it is possible to filter¹ the data by its ground returns. On the contrary, using the Cell Assignment Type argument equal Average or Minimum on unclassified data could (probably, 'would') result in bad DEMs. Mostly, the result will depend on the point cloud density, the terrain cover complexity, and the quality required in the output. It is important to (double) validate the DEM if going through this way.

• How to create DEM from Lidar point cloud data?

¹ Pay attention that to filter the LiDAR files in a LAS dataset it is necessary to generate a LAS dataset layer first (through the Make LAS dataset layer tool), or LAS dataset to Raster will consider all types of returns (just filtering using the LAS dataset properties for visualization won't work when processing data).

• Selecting LiDAR return point type in LiDAR dataset with ArcPy?
• Specifying LAS dataset filters in ArcGIS ModelBuilder?

Another option for creating DEMs in ArcGis is to use the combination of Las to Multipoint tool for filtering ground points, and then, Point to Raster (it is probably less efficient than the first method, though).

• LAS dataset to raster with ground points only

Other workflows for creating DEMs from LiDAR data in ArcGIS are described in the post below. It also has insights about aspects which should be taken into consideration, when generating DEMs.

• Proper workflow for LAS to DEM conversion

For working on DEMs starting from unclassified .las data I would suggest using more robust algorithms not yet available within the ArcGIS platform. For example:

• Determining bare earth DEM from unclassified LAS file?

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On the other hand, if the surface (raster) is a Digital Surface Model - DSM refer to the following posts:

Input of .las/.laz files and conversion to .asc DSM (LASzip and Fusion).

• Converting LiDAR data (.laz) to DSM in .asc format

Input of .las files and conversion to .asc DSM (LAStools).

• Converting LAS file to .asc DSM?

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Another option to import .las files in ArcGIS would be to convert them into ASCII (.txt, for example). Unless there is a specific reason for using plain text, previous options are better. The main differences working with .las or ascii files are approached in this post:

• Benefits of *.las vs *.xyz or *.ascii when working with LiDAR in ArcGIS for Desktop?

So, an alternative would be to use the command line LDA2ASCII from Fusion.

The LDA2ASCII syntax is:

LDA2ASCII InputFile OutputFile format

Suppose the following:

• Fusion is stored under c:\Fusion.
• the las file name is project.las.
• project.las is stored in: c:\Lidar.
• the new txt file will be saved at: c:\LiDAR.
• its name will be: project.txt

_{Hint: use an text editor to write Fusion's program commands (e.g. Notepad++). Save it with .bat extension. Then, write:}

Retrieve the following information: X, Y and Elevation.

c:\Fusion\LDA2ASCII c:\Lidar\project.las c:\Lidar\project.txt 0

Or if the .las files contain other information such as: Pulse, Return, X, Y, Elevation, Nadir and Intensity:

c:\Fusion\LDA2ASCII c:\Lidar\project.las c:\Lidar\project.txt 1

_{Save the .bat file, and then execute it (shortcut = F5)}

Open project.txt in ArcGIS.

Answer 2

In ArcGIS the workflow for importing LAS is to Import Las to Multipoint (tool of the same name) then create a terrain dataset. You can then use the Terrain to Raster tool if need be. (Required 3D Analyst)

Answer 3

What about LAStools? In particular lasgrid, las2dem, or las2tin. It has a GUI - lastool.exe now too.

Answer 4

There are also some options if you want to work entirely within ArcGIS. First, you need to make an LAS Dataset. This is basically a dataset with a symbolic link to your LAS files that ArcMap can read. Once you have this, you can filter, investigate, and view your point cloud. To create a DEM or other raster from the LAS data, you then need to use the LAS Dataset To Raster tool. If you want the ground elevations, you MUST make sure you have your LiDAR data filtered to display ONLY ground returns (use the LAS toolbar). If you want some other raster surface, filter your points accordingly. You will have many options, but make sure to use a grid cell size that is appropriate to the point spacing and to the analysis you want to do.

Edit: This is only available in the Advanced/ArcInfo level license.

Answer 5

If you have ArcGIS:

1. Use LAS To Multipoint (3D Analyst)
2. Create a terrain
3. Load Convert to DEM & add breaklines

There are tools here.