LAS Dataset
Esri Southwest User Conference September 17-19, 2012 | Denver, Colorado
Working with LAS Datasets David Vaillancourt
LAS Dataset - Overview •
LAS Dataset -
File based data structure
-
Stores references to LAS files on disk
-
Treats a collection of LAS files as one logical dataset
-
Optionally reference break-line data
LAS Dataset - Visualization •
In 2D (ArcMap) or 3D (ArcScene)
•
As points -
Symbolize using LAS attributes (Class Codes, RGB etc.)
LAS Dataset - Visualization •
As a surface -
•
Symbolize & filter using surface options (Bare-earth, First-return, etc.)
Control the number of points shown
LAS Dataset - Editing •
Manual editing (data errors, mis-classifications)
•
Using Geo-processing tools
LAS Dataset - Surface definition •
Support for break-lines (Surface constraints)
LAS Dataset - Analysis •
•
•
Derive surfaces -
LAS Dataset As Raster
-
LAS Dataset As TIN
Direct analysis -
Interpolate Shape
-
Add Surface Information
-
Line Of Sight
Rasterize on point metrics -
LAS Point Statistics As Raster
LAS Dataset - Spatial Reference Support •
LAS specification requires data provider to have georeferencing information in the header of the LAS file
•
If Data provider doesn’t have the correct information in the header… -
Assign spatial reference (if missing)
-
Override using a .prj file (if already present)
-
Project
Lidar data - Sharing •
•
Mosaic Dataset -
Manage lidar like imagery
-
Add / remove LAS files
-
Add / remove LAS datasets
Share the data as Image services -
Easy for others to see available Lidar data
-
Easy to download for project work
Airborne Vs. Terrestrial Lidar
•
•
Many tools geared towards airborne lidar -
Surface views and analysis tools
-
LAS attribute relevance
Terrestrial lidar supported as point cloud in ArcScene -
Points used as backdrop for measuring and digitizing
-
Display integrated with other GIS layers
DEMO
Usage Recommendations
•
Classified LAS files organized as ‘tiles’
•
200 MB file size limit (preferably ~50 MB)
•
All participating LAS files with the same Spatial Reference (Projected Coordinate System)
•
Data on a local disk
Challenges of Working with Lidar Data
•
Huge Volumes
•
Multiple Sources
•
Multiple Projections
•
Varying Accuracy
Licensing
•
Standard, 3D, or Spatial -
Create LAS dataset
-
Modify LAS dataset schema
-
Include in Mosaic dataset -
•
Publishing requires Image Server extension
-
View in 2D
-
Rasterize
3D -
Edit class codes
-
View in 3D
-
TIN based surface analysis
Working with LAS Datasets David Vaillancourt
LAS Dataset - Overview •
LAS Dataset -
File based data structure
-
Stores references to LAS files on disk
-
Treats a collection of LAS files as one logical dataset
-
Optionally reference break-line data
LAS Dataset - Visualization •
In 2D (ArcMap) or 3D (ArcScene)
•
As points -
Symbolize using LAS attributes (Class Codes, RGB etc.)
LAS Dataset - Visualization •
As a surface -
•
Symbolize & filter using surface options (Bare-earth, First-return, etc.)
Control the number of points shown
LAS Dataset - Editing •
Manual editing (data errors, mis-classifications)
•
Using Geo-processing tools
LAS Dataset - Surface definition •
Support for break-lines (Surface constraints)
LAS Dataset - Analysis •
•
•
Derive surfaces -
LAS Dataset As Raster
-
LAS Dataset As TIN
Direct analysis -
Interpolate Shape
-
Add Surface Information
-
Line Of Sight
Rasterize on point metrics -
LAS Point Statistics As Raster
LAS Dataset - Spatial Reference Support •
LAS specification requires data provider to have georeferencing information in the header of the LAS file
•
If Data provider doesn’t have the correct information in the header… -
Assign spatial reference (if missing)
-
Override using a .prj file (if already present)
-
Project
Lidar data - Sharing •
•
Mosaic Dataset -
Manage lidar like imagery
-
Add / remove LAS files
-
Add / remove LAS datasets
Share the data as Image services -
Easy for others to see available Lidar data
-
Easy to download for project work
Airborne Vs. Terrestrial Lidar
•
•
Many tools geared towards airborne lidar -
Surface views and analysis tools
-
LAS attribute relevance
Terrestrial lidar supported as point cloud in ArcScene -
Points used as backdrop for measuring and digitizing
-
Display integrated with other GIS layers
DEMO
Usage Recommendations
•
Classified LAS files organized as ‘tiles’
•
200 MB file size limit (preferably ~50 MB)
•
All participating LAS files with the same Spatial Reference (Projected Coordinate System)
•
Data on a local disk
Challenges of Working with Lidar Data
•
Huge Volumes
•
Multiple Sources
•
Multiple Projections
•
Varying Accuracy
Licensing
•
Standard, 3D, or Spatial -
Create LAS dataset
-
Modify LAS dataset schema
-
Include in Mosaic dataset -
•
Publishing requires Image Server extension
-
View in 2D
-
Rasterize
3D -
Edit class codes
-
View in 3D
-
TIN based surface analysis
