Lidar has
become an integral part of GIS mapping and analysis. Global
Mapper is well known for its ability to import, analyze, edit and export
Lidar datasets. With Global Mapper’s Lidar Module, advanced functionality
is leveraged through an easy to use Lidar
Toolbar. New
display options enables users to view points by height above ground to
visualize vegetation and building heights. Access to the Lidar Module
tools require a separate license*.
Light detection and ranging (Lidar) mapping, sometimes called 3D laser scanning, is a method for gathering precise geospatial information on the shape and surface characteristics for a specific collection area. The method for collecting Lidar data produces very dense, large files that can be cumbersome to handle. Global Mapper’s Lidar Module manages these large files with superior speed and efficiency.
Lidar data
is commonly delivered in two standard file format types: .LAS and .LAZ.
The LAS file format is a public file format for the interchange of 3-dimensional
point cloud, it is a binary file that retains the information specific
to Lidar data (unlike a generic ASCII). The .LAZ file format is a compressed
version of .LAS.
Importing
lidar data has been made easy in Global Mapper. Global Mapper offers native
support for LiDAR data. All ASPRS supported file formats (.las, .las,
.gz, .laz, .tar, .gz, .tgz, .zip) can be directly imported through the
Open Data Files
option in the File Menu. After
navigating to the saved file location and clicking open, the user will
be presented with the Lidar
Load Options dialog box. The
Lidar Load Options dialog box enables users to filter and grid
a point cloud prior to loading data into Global Mapper.
The
.LAS file format is a binary file format that maintains information specific
to a lidar dataset, without being very complex. Files with
the extension named as LAS should conform to the American Society of Photogrammetry
and Remote Sensing (ASPRS) LIDAR data exchange format standard.
Global Mapper has numerous tools for displaying and utilizing ASPRS Lidar
classifications, which were created for use with LAS formats 1.1, 1.2, 1.3, and 1.4. Point classification present in a Lidar file can vary by LAS version starting with the Lidar Load Options which
allows customized importation of the ASPRS defined point classifications
listed below.
0 Never classified
1 Unassigned
2 Ground
3 Low Vegetation
4 Medium Vegetation
5 High Vegetation
6 Building
7 Low Point (Noise)
8 Model Key-point (mass point)
9 Water
10 Railroad
11 Road
12 Overlap
13 Wire - Guard (Shield)
14 Wire - Conductor (Phase)
15 Transmission Tower
16 Wire-structure Connector
17 Bridge
18 High Point (Noise)
19 - 255 Reserved for ASPRS Definition
With the Lidar Module, you can manually classify lidar points, in addition to using lidar auto-classification tools on unclassified Lidar data. These classification tools are available in the Lidar Toolbar, and distributed throughout the application in various editing, load, and export menus.
Classification colors and groups can be controlled from the Filter Lidar Data tool. This allows for customizing the Lidar Classes and specifying the groups used in Automatic Lidar Classification tools.
The Lidar module provides a number of tools that can be used for quality checking the spatial location, point density and classification of Lidar data. For more information see QC of Lidar Data.
Global Mapper also allows you to automate the process of locating features on the ground using Lidar data. These automated feature extraction tools are available with the Lidar Module.
The Lidar Module also allows you to do Custom Feature Extraction using perpendicular path profile views.
* All content for the Lidar Module is included in the Global Mapper application. To access the Lidar Module tools, the license will need to be activated in a registered instance of the Global Mapper application.