US Fish & Wildlife Service: Global Mapper plays a key role in monitoring coastal habitats of mice

Gulf Island National Seashore
Imagery of the eastern end of Gulf Island National Seashore, Perdido Key, Florida, in 2010. This image is a mosaic of sand (light pixel) and vegetation (dark pixels) in the dune system in which the Perdido Key beach mice inhabit.

Monitoring a Coastal Dune Ecosystem

Cultivating a sense of moral responsibility for the environment involves more than public service announcements — it’s based on scientific knowledge.

A Peromyscus Polionotus

The U.S. Fish and Wildlife Service works to conserve and protect natural resources, such as species on the federal endangered list, through observing changes in the environment and what those changes impact. As one of the bureaus of the Department of Interior, the agency chooses Global Mapper to assist in this environmental research.

The bureau’s Spatial Ecologist Paul A. Lang specifically monitors the habitat of three subspecies of beach mice:

  • St. Andrew beach mouse (Peromyscus polionotus peninsularis)
  • Choctawhatchee beach mouse (Peromyscus polionotus allophyrs)
  • Perdido Key beach mouse (Peromyscus polionotus trissyllepsis)

The mice inhabit the coastal dune ecosystem along the northern Gulf Coast of Mexico in the panhandle of Florida – an area vulnerable to impacts due to tropical storm events and sea level rise. Lang is interested in gaining a greater understanding of the habitat for the long-term conservation of the beach mice. Lang uses Digital Terrain Models (DTMs) for 2015 in order to investigate sea level changes.

 

A Lack of High Resoultion DTMs

The most important consideration when embarking
on any GIS project is ensuring access to appropriate and clean data.

One of the challenges that Lang has faced in his work is the lack of a high resolution DTMs of the area in which the mice live for certain years. As a solution, Lang accessed publicly available Topobathy LiDAR data from the U.S. Army Corp of Engineers (USACE). This high density point cloud data was collected aerially and was obtained directly from the USACE and from the National Oceanic and Atmospheric Administration’s (NOAA) data clearinghouse.

In order to integrate this data into his research, Lang needed software that had the tools for generating accurate DTMs from the LiDAR data without a steep learning curve.

Raw LiDAR point cloud
The raw LiDAR point cloud with pre-classified ground points used in Global Mapper to generate the final DTM.

Generating DTMs in Global Mapper

Lang chose to use Global Mapper and the accompanying LiDAR Module for his habitat mapping.

With a few simple steps, he generated the high resolution DTMs he needed for his research. First, he imported the .las files into Global Mapper and cropped them down to the area of focus. After visualizing and examining the characteristics and metadata of the point clouds in the software, Lang determined that further classification and clean-up was unnecessary. Second, he examined the inherent statistics of the data to get a better sense of the resolution he could create in the resulting DTMs. Third, he used the Create Elevation Grid tool to generate several DTMs that tested different values of No Data distance in order to fill gaps in the point clouds. After these tests, Lang arrived at high resolution DTMs based on the LiDAR data he obtained from the USACE.

From there, Lang was able to use the Simulate Water Level Rise functionality in Global Mapper to visualize potential water inundation on the mice habitat.

Shell Island and St. Andrew State Park
Shell Island and St. Andrew State Park with the Choctawhatchee beach mice critical habitat boundaries overlaid.

The Benefits of Global Mapper

According to Lang, he chose Global Mapper for his analysis because he didn’t find other software as “straight-forward” for processing LiDAR data. Global Mapper’s easy-to-use platform allowed Lang to quickly and accurately generate the high resolution DTM he needed without taking time away from his research.

Global Mapper allows for easy visualization, editing, and filtering of LiDAR and other point cloud datasets. The addition of the LiDAR Module, expands this functionality with auto-classification tools, automatic and custom feature extraction, point filtering options, and numerous other point cloud editing capabilities.

1-meter DTM
The 1-meter DTM generated using the pre-classified ground points contained in the LiDAR data from USACE.

About Global Mapper

Global Mapper is an affordable and easy-to-use GIS application that offers access to an unparalleled variety of spatial datasets and provides just the right level of functionality to satisfy both experienced GIS professionals and beginning users. Equally well suited as a standalone spatial data management tool and as an integral component of an enterprise-wide GIS, Global Mapper is a must-have for anyone who deals with maps or spatial data. The supplementary LiDAR Module provides a powerful set of tools for managing point cloud datasets, including automatic point classification and feature extraction.

About Blue Marble Geographics

Since the early 1990s, Blue Marble Geographics has been a pioneer in the development of powerful and innovative geospatial software. Widely regarded for its expertise in coordinate conversion and file format support, Blue Marble’s products include Geographic Calculator, the paradigm for highly accurate spatial data conversion and advanced projection management; Global Mapper, a fully-functional and affordable GIS application; and the Global Mapper LiDAR Module, a suite of powerful point cloud processing tools.

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