Ecohydrology & Terrain Analysis - Overview
ENV 761 - Landscape GIS | Spring 2024 | Instructors: Peter Cada & John Fay
Overview
In this section we explore all the amazing things you can do with digital elevation model data, particularly with respect to deriving hydrologic data and terrain datasets useful in examining landscapes from an ecological perspective.
Sections & Learning Objectives
| Topic | Learning Objectives |
|---|---|
| §2.1 Ecohydrology [PPT | Recordings ] |
• Explain the difference between “elevation” and “terrain” • Describe how ecology and hydrology interact and why it’s important • Define the terms “basin”, “watershed”, and “catchment”; explain how they’re different • List at least two ways used to characterize different drainage areas • Explain how flow direction is calculated, and how sinks affect that calculation • Explain how sinks are dealt with to create a depressionless DEM • Describe how the flow direction result facilitates more hydrological analysis • Explain how flow accumulation is calculated and what a particular cell value means in its result • Describe how a stream network can be approximated from a flow accumulation raster • Describe how drainage areas are determined from a flow direction and pour point dataset • Compare the different flow direction methods: D8, MD8, D-inf, and MD-inf • Explain how flow length is calculated and what its result represents (upstream & downstream) |
| §2.2 Terrain Analysis [PPT | Recordings] |
• Understand the link between terrain and vegetation community partitioning • Explain broad patterns in biodiversity in terms of temperature and moisture availability • List various landscape-scape factors that affect the temperature, radiation load, moisture, and soil characteristics of an area • Explain how slope, aspect, and hillshade rasters are derived using ArcGIS tools • Use the Hillshade tool to generate a raster proxy for solar radiation load • Explain how Topographic Convergence Index (TCI) approximates moisture & compute TCI from a DEM. • Compute Topographic Position index from a DEM and describe how the choice of neighborhood size affects alters the output • Compute Slope Position from different scale TPI products and explain what it shows • Compute Land Form from different scale TPI products and explain what it shows |
| §2.3 Riparian Analysis [PPT | Recordings] |
• Create watershed-based planning units • Use flow length to identify riparian areas • Identify flood plains using the watershed tool |