Texas Statewide Vegetation Map

Vegetation maps are needed for habitat analysis, fire mitigation and response, water resource and environmental impact analyses, and more. These projects often include massive amounts of data, from lidar and aerial photography to ground GPS and classification work. Vegetation project data and output must be accessible to people in a way that they can use it.

The Texas Parks and Wildlife Department (TPWD) is using GIS to create a new land classification map of the state to get insight into the vast and diverse habitats and to comply with a state mandate. The department used Esri’s ArcGIS to simplify this otherwise onerous task. The software made it possible for staff to use a complete system approach that includes data management, mobile data collection and in-field data analysis, rich analysis tools, and server technology for hosting map service applications that make interactive vegetation map data easily accessible from thin clients. 

The department’s Texas Ecological Systems Database Project produces vegetation datasets of Texas by section. The state is divided into six sections, and data is compiled for these in phases.Three phases have already been completed including the eastern half of the state. The data and maps are accessible online.

One of TPWD’s goals for the project was to expand its user community beyond hard-core GIS users to include landownership, general land management, and academic communities. TPWD’s GIS group, headed by Kim Ludeke, PhD, used ArcGIS Server and ArcGIS Viewer for Flex software out of the box to create web apps that aid data interpretation and dissemination. The outcome is a vegetation community map that is useful for planning and analysis at parcel and individual landownership levels.

Data, data, and more data has been the order every day of the project. Data comes from any sources such as The Nature Conservancy (TNC), United States Fish and Wildlife Service, Natural Resources Conservation Service (NRCS), and The Geologic Atlas of Texas, which contains 1:250K surface geology data for the entire state.

Amie Truer-Kuehn is TPWD’s plant ecologist who works in the field identifying plant communities, storing her interpretation and documenting support. Working with ArcGIS Mobile, she has collected 10,000 ground truth data points from the field and loaded them directly into a file geodatabase. This data collection process, or ground truthing, involves a roadside survey of the plant communities. Avoiding urban areas, she selects areas of counties accessible via county roads. She is able to survey parks and wildlife properties and TNC properties more thoroughly because she can access these lands and has data sharing permissions.

While on the road, Truer-Kuehn stops every mile to collect data. She also stops for riparian zones and rare vegetation communities. The data she collects includes GPS location (latitudelongitude) and attributes of land cover (e.g., grassland, shrubland), cover percentage (wood components, herbaceous), dominant species (topthree species), and ecological systems and subsystems. These attributes are listed in the vegetation map legend.

From the ground, it is hard to see the forest for the trees. Through the lens of her laptop, the ecologist has a comprehensive view of the landscape. She sees satellite imagery and aerial photography and uses a GPS while the mapping environment is open to get the complete context of the landscape in her immediate location. Furthermore, she can see underlying soils, slopes, digital elevation model (DEM) data, and one-meter true- and false-color infrared aerial photography, all of which has been loaded onto her laptop.

Using domains in the file geodatabase, Truer-Kuehn manages data input from the field and performs data cleanup on-site. She can upload her data to the project’s GIS platform from the field or from her hotel room at night. The domains simplify the task of parsing out data to different partners who do other analysis and spatial segmentation of the data.

The GIS group uses ArcGIS Online basemaps for the project’s map service. ArcGIS Server performs raster processing in the web app. Using ArcGIS Viewer for Flex, staff created an ID tool that can be used in a browser, enabling the light client user to turn on a vegetation layer, ID a pixel, and select various base layers. The user can also turn the vegetation layer off; look at the underlying aerial photography; click in an area; and while looking at true-color photography, see the vegetation type.

The Texas Ecological Systems Database Project allows users to perform a host of studies. For example, TPWD is using it to evaluate the quality of riparian vegetation. Considering USGS-defined hydrologic units and vegetation data layers, project analysts use GIS to see where riparian corridors are thriving and assess the impact that reservoir projects have on different vegetation types. They also see how much water is needed to maintain the ecosystems of various floodplains, in-stream ecosystems including fisheries within the banks, and the riparian areas along stream banks.

The department’s Inland Fisheries Division uses GIS to study data related to an endemic bass species—the Guadalupe bass. This fish is only found in the smaller, clearwater streams and rivers of two watersheds in the hill country of Texas.Staff use map data to manage and create plans for watershed area management and improve stream quality for the bass.

The project helps the department comply with  Texas legislative mandate, Senate Bill 3, that requires that the department study the state’s water resource needs and different aspects involved in water planning. TPWD uses GIS to model the water supply limits for estimated population growth, which provides strategic information for reporting and planning.

The Texas Forest Service taps the Ecological Systems Database Project for fire risk modeling as well as forest management projects such as a long-leaf pine restoration project. US Forest Service also accesses the database project to find rare species by using rare plant and animal species modeling.

TPWD’s next ArcGIS upgrade and the addition of the ArcGIS Server Image extension will add more functionality to the web application. From the browser, users will be able to click and send data as they need it. TPWD plans to do another statewide vegetation project in 10 years to compare vegetation change. Funding for the Ecological Systems Database Project was provided by the US Fish and Wildlife Service  State Wildlife Grant program and the Texas Water Development Board StratMap program.

From ESRI Forestry GIS Journal, Spring 2011
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