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Data types supported by a LAS dataset

The main data sources for LAS datasets are lidar data stored in LAS format files (*.las, *.zlas, and *.laz), and surface constraints stored in feature classes. zLAS and LAZ files are compressed versions of LAS files.

Lidar and point cloud data

General characteristics of point clouds include the following:

  • Lidar (light detection and ranging) point clouds stored in .las file format

  • Not surface specific

  • Sampled to required nominal point spacing, varying from 1 to 3 feet (approximately 0.2 to 1 meters) depending on application

  • Every point contains attributes that are stored with the x,y,z data

  • Large quantities of point data

  • Photogrammetric point cloud data can also be stored in .las files

Compressed lidar formats

Two compressed lidar formats are supported in ArcGIS Pro: *.zlas and *.laz files. They are both losslessly compressed version of a LAS file. Compressed lidar formats are optimized versions of LAS files, which is useful for archiving, sharing, and direct use in ArcGIS Pro. Compressed lidar formats files are much smaller and much easier to share over networks, than regular LAS.

General characteristics for ZLAS format include the following:

  • You can add *.zlas files to a LAS dataset using the LAS dataset properties dialog or by using the Create LAS Dataset geoprocessing tool.

  • You can see individual *.zlas files in the Catalog pane, and drag and drop them into a map or scene in ArcGIS Pro.

  • A spatial index and statistics are generated for *.zlas files when they are created. They are embedded into the *.zlas files and improve overall performance and usability. LAS datasets referencing *.zlas files will automatically use the statistics available for those files.

  • A pyramid can be built for a LAS dataset referencing *.zlas files.

  • You can run geoprocessing tools to create derivative products from a LAS dataset referencing a *.zlas files or on individual *.zlas files.

  • You can edit class codes and class flags from a LAS dataset referencing *.zlas files or on individual *.zlas files.

General characteristics for LAZ format include the following:

  • You can add *.laz files to a LAS dataset using the LAS dataset properties dialog box or by using the LAS dataset properties dialog and the Create LAS Dataset geoprocessing tool..

  • You cannot see individual *.laz files in the Catalog pane, nor can you drag them to a map or scene in ArcGIS Pro. They must be added to a LAS dataset to be used in ArcGIS Pro.

  • You can calculate statistics for a LAS dataset and its referenced *.laz files to understand what class codes and other attributes that are available in the *.laz files.

  • A spatial index is created for *.laz files when statistics are calculated.

  • A pyramid can be built for a LAS dataset referencing *.laz files.

  • You can run geoprocessing tools to create derivative products from a LAS dataset referencing a *.laz file.

  • You can not edit class codes and class flags from a LAS dataset referencing *.laz files.

Surface constraints

Surface constraints are surface features stored in geodatabase feature classes, which are usually derived from a remote sensing technique such as photogrammetry.

Characteristics of photogrammetrically derived breaklines include the following:

  • Surface-specific breaks in slope along linear features

  • Natural landforms (for example, ridges and valleys)

  • Terrain features resulting from earthworks (for example, bulldozed)

  • Lake shorelines, creeks, or river shorelines

  • Edge of road pavement

  • Delineation of void areas (typically obscured by vegetation)

  • Minimal attribution

  • Typically moderate quantities

Characteristics of GPS points include the following:

  • Irregularly spaced

  • May or may not represent surface-specific peaks and pits

  • Used for control, QA, and benchmarking other data

  • Property boundary control points

  • Potentially significant attribution per point

  • Typically small quantities

The following table describes the types of surface constraints that can be used.

Surface constraint type

Feature class

Z-value source in the feature class

Example data

Points (x,y,z locations)

Point feature class

Can be either of the following:

  • Shape geometry; x,y,z per vertex

  • Attribute column containing one z-value per shape

  • Spot heights

  • Survey points

  • GPS points

Polygon feature class
  • Shape geometry; x,y,z per vertex

or

  • Attribute column containing one z-value per shape

Shoreline delineation

Breaklines (hard or soft)

Line feature class

  • Shape geometry; x,y,z per vertex

  • Attribute column containing one z-value per shape

  • No height source; z-values interpolated for each feature from the surface before being added

  • Contours

  • Edge of pavement

  • Water lines (streams, rivers, canals, and shorelines)

Polygon feature class

  • Shape geometry; x,y,z per vertex

  • Attribute column containing one z-value per shape (such as a shoreline)

  • No height source; z-values interpolated for each feature from the surface before being added

Lake shoreline

Clipping polygons (hard or soft)

Polygon feature class

  • Shape geometry; x,y,z per vertex

  • Attribute column containing one z-value per shape (such as a shoreline)

  • No height source; z-values interpolated for each feature from the surface before being added

Study area boundary

Erase polygons (hard or soft)

Polygon feature class

  • Shape geometry; x,y,z per vertex

  • Attribute column containing one z-value per shape

  • No height source; z-values interpolated for each feature from the surface before being added

  • Lake shoreline

  • Obscured areas (dense forest canopy)

Replace polygons (hard or soft)

Polygon feature class

  • Shape geometry; x,y,z per vertex

  • Attribute column containing one z-value for all vertices in each shape

Water bodies