GEOG 487
Environmental Applications of GIS

Lesson 4 Overview


Lesson 4 Overview


In Lesson 3, we created several custom datasets for our study area wetlands within the Ottawa National Wildlife Refuge. These data contain information about plant species, vegetation groups, and invasive species for five snapshots in time between 1939 and 2005. In Lesson 4, we will use these datasets to understand how vegetation changes in response to water level fluctuations. In particular, we are interested in how emergent vegetation changes, since this group of plants provides the highest quality habitat in the wetland. We are also interested in how invasive species spread over time. Comparing multiple datasets over many time periods can get a bit complicated. In this lesson, we will explore several tools to make it easier to identify trends over time between multiple datasets.


Lesson 4 is a continuation of the scenario from Lesson 3 - "You are part of a research team tasked with creating a restoration plan for a degraded wetland complex. You need to understand how the vegetation within the wetland has historically responded to changes in water levels. This information will enable you to predict the health of the wetland in future scenarios, including anticipated hydrological changes due to climate change. You begin by searching for publicly available sources of data for your analysis. You find that there is not a dataset that has sufficient detail about vegetation for your study area. Furthermore, you are unable to find a dataset that shows wetland vegetation at multiple points in time. Your team hires a remote sensing specialist to acquire and interpret historical imagery and digitize polygons representing vegetation over time. Your job is to figure out how to use the vegetation data and GIS software to understand the relationship between fluctuating water levels and changes in vegetation."


At the successful completion of Lesson 4, you will have:

  • explored and interpreted results from GIS operations;
  • used ArcGIS tools to visually compare multiple datasets (e.g., time-series data);
  • used ArcGIS tools to statistically compare multiple datasets.


If you have questions now or at any point during this lesson, please post them to the Lesson 4 Discussion.