Much of what we build has an impact on the environment, from the highways we drive to the homes in which we live. The gas that fuels our stoves and cars is pumped to us via underground pipelines that span dozens of states. The electricity generated to power commercial offices is provided by electric power lines. And while we try to remain as green as we can and read from the screen, we rely upon timber plantations to generate our paper products. Where do these impacts occur? To what extent do they impact the environment?
A geographic information system (GIS) is used to answer these questions in almost every field imaginable. In fact, utility companies, government agencies, banks, weather stations, emergency responders research institutions, land use planners, health organizations, and security agencies, to name a few, all rely on locality data. But GIS is especially important to an Environmental Consultant. This essential tool allows us to investigate the extent of our environmental impacts.
What is GIS?
A geographic information system (GIS) is used for storing, managing, and displaying geopatial data. Most commonly, data in the form of a shapefile or coverage is used to create a map that can be exported and printed or used as a web application. The ArcGIS suite is a licensed mapping software produced by the Environmental Systems Research Institute (ESRI). Other GIS systems are also on the market, including the open-source QGIS and GRASS GIS. These systems are not unlike the Adobe or Microsoft Office suites for mapping. They are large programs with multiple extensions that may be used to perform a variety of services.
A GIS works by referencing a plane coordinate system, where map features are expressed as x- and y-coordinates. Conversely, locations on the Earth’s surface are based on a geographic coordinate system, where features are expressed in latitude and longitude. By projecting the Earth’s surface as a plane, a map projection is created, and map points may be added and georeferenced to real world locations.
Because the earth is not a perfect sphere (there are rather large, bumpy mountains, and shallow lakes, for example), we approximate Earth using a datum. This serves as a reference for calculating the geographic coordinates of a location. We can use different datums depending on where we are, or transform our current projection to a different one, so that our map features represent accurate real-world locations. In the example above, the red datum fits North America, but does not accurately represent Europe. A different datum may be used (blue) as a better fit.
The Mapping Process
In order to understand what we are impacting, we first need to know what resources are there. Baseline studies including floristic and faunal surveys are typically conducted by graduate students and professors of biology, natural resources, or environmental science. Environmental consulting offers many instances where baseline studies are also performed. State and federal government agencies, like the Natural Heritage Program with the Tennessee Department of Environment and Conservation (TDEC) and the United States Fish & Wildlife Service (USFWS) also inventory the existence and health of our resources.
During a field survey, biologists will locate streams, wetlands, species, and habitats using a GPS. We will physically walk boundaries around these resources in order to collect their locations. This data is then offloaded from the GPS onto a computer as a shapefile. Most GPS data must be "post-processed," or differentially corrected prior to data analysis.
Once the data has been collected, we are ready to pull it into our mapping programs to analyze it further. Below, we plotted vector data (georeferenced or field-collected points, lines, and polygons) on top of raster data (continuous data, like elevation, gives us a background image). We can display this data in a variety of colors and shapes, depending on the type of map you are trying to create. Below is an example of the types of data normally collected during a red flag analysis. We can query these points to tell us how far away one point is from another, how large a space is, and what the precise GPS coordinates are.
Mapping Environmental impact
So how is GIS used in a typical Environmental Consulting project?
A local developer would like to build a new high school on a forested plot that has been previously logged. There are two wetlands and a stream along the edge of the property that will not be affected by the building footprint. However, it was noted that a population of rare plant species will be clipped by the building footprint. How large is this rare population? How close will the development or any construction activities come to the species? An environmental consultant would document the boundary of the population, contact the appropriate agency, and transplant those rare species to another location. In some cases, the developer may need to make changes to the plan itself. This situation is not unlike a typical environmental consulting project, and is relatively straightforward. But project impacts get much larger and more complex.
Another developer would like to build a solar farm in Tennessee. The National Wetlands Inventory (NWI) map does not recognize any wetlands within the footprint of the panels, but you located two. Where is the boundary? Will you need a permit to impact those wetlands? How will we mitigate for those impacts? The GPS you used in the field collects the necessary boundary data you need to calculate impacts acreages in GIS. These totals will be added to your permit package and sent to the appropriate state and federal agencies.
Finally, we impact our environment whenever we build long linear projects, including new roads, pipelines, or powerlines. Pipelines and powerlines create temporary impacts to our environment, as herbaceous and shrubby vegetation typically regenerate over the scar. Roads, however, are permanent impacts, and we must therefore plan these projects carefully. A common solution to these larger, linear projects is through the use of Network Analysis. We can use GIS tools and extensions to identify the best place for a linear project, considering the slope, aspect, distance, environmental resources, soil type, and any other factor associated with the project area. Finding a solution that works both for the environment and the client can be challenging, and we rely heavily on GIS to help.
WHERE DO YOU START?
There are a number of ways to learn GIS. If you are unfamiliar with the free, open-source platform, QGIS, download it here. QGIS is a volunteer driven project that welcomes contributions in the form of code, bug fixes and reports, contributed documentation, advocacy and supporting other users. We recommend you contact Randal Hale of North River Geographic Systems Inc. for classes and open-source support.
You may also enroll in free ArcGIS modules through your University. To find out whether or not your University offers these classes, contact the GIS Department. If you are a student at UTC, we recommend you contact Charlie Mix (Charles-Mix@utc.edu) with the IGTLab. Not only will you learn how to use the software, Charlie's students complete a variety of real-world projects throughout the southeast.
Finally, Circadian is always looking for Environmental Science or Biology students, recent graduates, and volunteers to help us on our projects. Circadian is equipped with ArcMap and Spatial Analyst, which we use to create high quality mapping as part of the Environmental Consulting process. If you are interested in working with us in this capacity or any other, please Contact Us.