Using lidar in ArcGIS

ArcGIS supports lidar data provided as LAS (or ASCII) files. There are three different formats (datasets) that can be used to manage and work with your lidar data in ArcGIS depending on your needs, which include the LAS dataset, terrain dataset, and mosaic dataset.

ArcGIS datasets that support lidar data

LAS dataset

Mosaic dataset

Terrain dataset

ArcGIS applications

ArcCatalog, ArcScene, ArcMap

ArcCatalog, ArcGlobe, ArcMap

ArcCatalog, ArcGlobe, ArcMap

Storage locations

File system

Geodatabase

Geodatabase

Relationship to LAS source files

Points to

Points to

None

Size limitation

Limited by space on disk

Limited by size allowed by geodatabase

Limited by size allowed by geodatabase

Surface constraints

Supported

Not supported directly(supported if present in LAS dataset or terrain dataset)

Supported

Lidar inputs

LAS files

LAS files, terrain datasets, LAS datasets

Multipoint feature class

Types of lidar

Airborne and terrestrial

Airborne

Airborne

Rendering

Points, triangulated surface viewed in 2D and 3D

Raster

Triangulated surface

Analysis

Tools that can ingest point clouds or TINs

Use with 3D Analyst tools

Use with LAS dataset tools

Learn about analysis using LAS datasets

Use with tools that can ingest raster data

Use with Spatial Analyst tools and other raster dataset tools

Learn about analysis using raster data

Tools that can ingest TINs or raster datasets

Use with 3D Analyst tools

Use with Spatial Analyst tools and other raster dataset tools

Learn about analysis using terrain dataset

Display

Thinned points

Can change display by choosing different class types or data types

Display is modified using the LAS dataset toolbar or the layer properties dialog box

Uses cache for faster display

Can change display by choosing different class types or data types

Display is modified using the layer properties dialog box or the Image Analysis window

Thinned points based on pyramids

Can change display by choosing different class types or data types

Display is modified using the layer properties dialog box

Editing points

Can edit the points residing in the LAS files

Cannot edit points

Can edit the LAS points as multipoints referenced by the terrain dataset

Combining with data

Supports LAS files, feature classes, and shapefiles

Supports LAS files, LAS datasets, terrain datasets, and other raster formats

Supports LAS and feature classes

Comparing the LAS dataset, mosaic dataset, and terrain dataset

Using lidar as a LAS dataset

The LAS dataset provides fast access to large volumes of lidar and surface data without the need for data conversion or importing. It makes it easy to work with several thousand LAS files covering an entire administrative area or perhaps just a few LAS files for a specific study area. It allows you to examine LAS files quickly, providing detailed statistics and area coverage of the lidar data in the LAS files.

A LAS dataset can be:

Many tools for the LAS dataset were designed for airborne lidar where surfaces are commonly interpreted from the point cloud. For example, with airborne lidar it makes sense to toggle on TIN based surface views or to interpolate raster DEMs. Terrestrial lidar, on the other hand, tends to be more immersive and is often only valid to view and use as a point cloud. ArcGIS doesn't know what kind of lidar you have so it's up to you to use it appropriately. For the most part, terrestrial lidar should just be used and viewed in ArcScene as points. The points can be used as a backdrop for digitizing measurements and features and be displayed in an integrated fashion with other GIS layers.

Learn about airborne and terrestrially collected lidar

Using lidar with the LAS dataset 3D View

Viewing LAS datasets using a 3D perspective is a great way to better visualize and understand the lidar data referenced by the LAS dataset. The LAS dataset 3D View window allows you to view your LAS dataset as points or as a surface in a 3D environment in ArcMap. The 3D view is only available from the LAS Dataset toolbar in ArcMap. 3D perspectives may make it easier to recognize particular features captured from lidar data, such as surface valleys, mountain peaks, buildings, vegetation types, forest canopy, road corridors, river/stream corridors, mines, construction sites, towers, and even power lines. Drawing these features in 3D allows you to validate your lidar data in GIS and enables you to make informed analytic decisions.

Learn more about the LAS dataset 3D View

Using lidar with the LAS Dataset 2D Profile Viewer

A common way to visualize, analyze, and edit lidar data is to use a 2D cross-sectional view. A selected set of lidar points from a LAS dataset can be displayed and edited using the LAS dataset Profile View window accessed from the LAS Dataset toolbar in ArcMap. Visualizing cross sections of lidar data allows you to analyze collections of points from a unique perspective. 2D profile perspectives may make it easier to recognize particular features captured from lidar data, such as surface valleys, mountain peaks, buildings, vegetation types, forest canopy, road corridors, river/stream corridors, mines, construction sites, towers, and even power lines. Drawing cross sections of these features allows you to validate your lidar data in GIS and enables you to make informed analytic decisions.

Using the Profile View window, you can do the following:

  • Measure distances and heights between points.
  • Manually edit and update LAS classification codes.
  • Manually edit LAS point-bit field flags.
  • Display full-resolution lidar point sets.
  • Select the LAS dataset 3D View LAS Dataset 3D Viewer window to visualize the selected LAS dataset point set in 3D.

Learn more about the Profile View

Editing LAS files

LAS datasets can be edited to make updates to the source LAS files or the lidar points in the source LAS files. LAS datasets can be edited to fix problems, make improvements, and increase or decrease the data area extent.

The list below includes common examples of how you can benefit from editing LAS datasets:

  • Manually fix errors in class codes.
  • Visually compare the lidar points against existing GIS data for data validation, such as building data.
  • Classify lidar points using GIS features.
  • Reclassify lidar points manually selecting one or many lidar points.
  • Change entire classification codes currently in the LAS dataset.
  • Add or remove LAS files from a LAS dataset to increase or decrease the data area extent.
  • Add or remove other GIS surface features, known as surface constraints, to/from the LAS dataset.
  • Interactively measure 3D distances between visible features, such as power lines and trees.
  • Use the lidar points as backdrop data to digitize in new GIS features, such as street furniture.
  • Assign a spatial reference to a project if necessary.

Learn more about editing LAS files in ArcGIS

Using lidar as a terrain dataset

A terrain dataset is a TIN-based dataset that uses geodatabase feature classes as data sources. A triangulated irregular network (TIN) is a data structure used to model surfaces—such as elevation—as a connected network of triangles.

To add lidar (LAS files) to a terrain dataset, they are imported into a multipoint feature class in a geodatabase feature dataset. The terrain dataset is then generated within this feature dataset and can encompass much more than just the lidar data.

Terrain datasets will help you with the following:

Using lidar in a mosaic dataset

By adding your lidar data to a mosaic dataset, it can be used and rendered as a raster. This allows you to

The mosaic dataset is similar to the LAS dataset, in that it stores a pointer to the original dataset and does not move all the points from one format into another, therefore, being quick to create, small in file size, and easy to update with additional LAS files. Alternatively, you can convert your LAS files or LAS dataset to a raster dataset.

You can also use a mosaic dataset to catalog all your lidar data.

Learn about adding lidar data to a mosaic dataset

Related Topics

6/3/2013