Lecture 25 - Geographical Information Systems (GIS)

Introduction to Geographical Information Systems (GIS)

• Background and Context: This lecture, presented by Anthony Rendell, serves as a direct continuation of the previous material on GPS. It focuses on the transition from simply collecting spatial data to analyzing and understanding the world through that data.

• Core Objectives:

  • Learn the methods for mapping the world from a distance.

  • Examine the use of spatial information from GPS, satellites, and laser radar (LiDAR).

  • Define what spatial information is and how geographical information systems function.

  • Explore real-world case studies involving wildlife management and ecosystem monitoring.

Defining Geographical Information Systems (GIS)

• Definition: GIS stands for Geographical Information System. It acts as a framework or computer system designed to implement, manipulate, store, and analyze spatial data.

• Software Options:

  • ArcGIS: Frequently cited as the most common industry-standard GIS platform.

  • Open Source Alternatives: Includes applications such as QGIS, GRASS, RDGEL, and GALD.

• Spatial Information: Refers to data that identifies the geographical location of features on Earth. This requires the definition of a specific coordinate system (consistent with GPS usage) to accurately map the surface of the planet.

Key Functions and Capabilities of GIS

• Data Integration and Manipulation: GIS allows users to incorporate various data types, including points, lines, and polygons collected via GPS units.

• Storage and Retrieval of Remote Sensing Data: The system can process large-scale imagery, such as photos taken by satellites. Users can quantify spatial locations based on the Earth's surface within the software.

• Metric Generation and Quantification: GIS enables researchers to calculate landscape metrics without physical field visits. Examples include:

  • Measuring the number and length of roads in an ecosystem.

  • Identifying and quantifying habitat patches in aerial photographs.

• Spatial Querying and Analysis: Examples of specific queries include determining the exact distance between two specific points (e.g., measuring distances between campsites on a three-day hiking track to provide resources for hikers).

Advanced Environmental Data: LiDAR

• LiDAR Mechanism: LiDAR stands for "light detecting radar." It involves flying a drone or aircraft over a surface and dropping a laser beam at specific intervals (e.g., every $1\,cm$).

• Calculation of Height: The system records the time it takes for the laser to hit the surface and return to the sensor. This data is used to calculate the height of various elements in the landscape.

• Case Study: Phillip Island:

  • LiDAR was used to map areas including Cowes (the main township), Osman Roberts Reserve, Rhyll Inlet, and Ventnor Koala Reserve.

  • Applications: Analyzing tree canopy height and habitat structural complexity in contrast to open agricultural paddocks. This structural data helps researchers understand if species like wallabies prefer certain areas based on the complexity of the vegetation.

Global and Local Applications of GIS

• Weather and Storm Prediction: GIS is used for global cyclone modeling. By analyzing weather data, systems can predict the trajectory of a storm, allowing towns to prepare for landfall.

• Urban and Agricultural Planning:

  • Resource Allocation: Planners can analyze human density relative to existing infrastructure. For example, a new school might be placed in an area with high human density but the furthest distance from existing schools.

  • Healthcare: Similar spatial trend analysis is used to determine the placement of new hospitals.

• Emergency Response:

  • Ambulance Logistics: GIS helps dispatchers track ambulance locations and estimate arrival times.

  • Bushfire Management: GIS can map fire boundaries and predict spread rates. Factors like topography are integrated; for instance, a fire may move $2\times$ as fast uphill and only $0.5\times$ as fast downhill.

The Thematic Layer System

• Concept of Layers: GIS works by overlaying various "thematic layers" that represent different types of data.

• Examples of Common Layers:

  • Point Layer: Specific locations (e.g., GPS points from field surveys).

  • Base Map Layer: Often use aerial photography or platforms like Google Earth as the foundational visual layer.

  • Usage Layers: Data indicating land use (urban vs. rural) or road networks.

• Spatial Alignment: All layers are perfectly aligned based on their geographic location. This allows a researcher to click on a single point and simultaneously extract information regarding its zoning, topography, wetland proportion, and population demographics.

Case Study 1: Predicting Species Distribution (Koalas)

• Researcher: Kita Rashman (Deakin PhD candidate).

• Location: Southwest Victoria, specifically near Portland.

• Objective: To understand how plantation forestry and harvesting influence koala abundance and to define pressure zones for management.

• Methodology:

  • Double count surveys were conducted across national parks, fragmented habitats (linear roadside strips), and plantation forests to determine density.

  • Landscape Variables Analyzed:

    • Roads: Found a negative correlation; higher road length in a $1\,km$ buffer led to lower koala abundance.

    • Vegetation Type: Analysis of dominant species, specifically Eucalyptus viminalis (a preferred food source). Abundance increased linearly with the availability of this food source.

    • Plantation Cover: A higher proportion of plantation forest correlated with higher koala abundance.

    • Soil Organic Carbon: High-quality soils support high-quality plants, which in turn support more koalas. An East-West trend in soil quality was mapped using GIS.

• Output: A predictive distribution map showing densities ranging from $0$ to $8 \text{ koalas per hectare}$. This map helps target management efforts and predict the impact of future land-use changes.

Case Study 2: Monitoring Ecosystem Trends (Mangroves)

• Researcher: Kelvin Lee (Deakin PhD candidate).

• Location: Hukong Valley Wildlife Sanctuary, Myanmar.

• Objective: Tracking global ecosystem loss to determine if conservation actions are effective.

• Methodology: Using satellite remote sensing data to perform land cover classification.

• Image Classification: Computers identify individual pixels based on infrared, red, blue, and green bands. Since different plants have unique chemical signatures, they appear differently in infrared imagery.

• Change Detection:

  • The study compared imagery from the year $2000$ to $2018$.

  • Categories: Mangrove areas (green), cleared areas (yellow), and water (blue).

  • Findings: By comparing pixels over time, the researcher identified a slight but significant decline in mangrove extent.

• Challenge of Cloud Cover: Images obscured by clouds (shown in gray in the dataset) were filtered, yet a clear trend of decline was still demonstrable through spatial analysis.

Case Study 3: Population Ecology (Long-nosed Potoroos)

• Researcher: Meg Farmer (Deakin Honors student).

• Location: French Island.

• Objective: To understand the movement and habitat use of long-nosed potoroos, a species that survives on French Island despite the presence of feral cats.

• Methodology:

  • GPS Tracking: GPS units were attached to the tails of potoroos using sports tape. These units included a whip antenna for radio tracking to assist in recovery.

  • Data Retrieval: The tape typically loses its stickiness and slides off the tail after approximately $3 \text{ weeks}$ of wear, at which point the units are collected.

• Analyses:

  • Home Range Estimators: GIS was used to determine the animal's full range versus its core activity areas.

  • Core Areas: These darker circles represented site-faithful nesting sites.

  • Broad Ranges: These represented foraging areas.

• Results: The GIS data confirmed that potoroos primarily use dense vegetation to avoid cat predation. The data showed significant range overlap among males, suggesting shared foraging grounds while maintaining distinct nesting areas.

• Management Impact: This information informs revegetation strategies to maintain habitat corridors that protect potoroos from cats.

Practical Application for Students

• GIS in Professional Practice: GIS is now a foundational tool for nearly all environmental scientists. Full proficiency requires time and patience.

• Curriculum Pathway: Students will take a specialized unit in GIS in their third year to deepen their technical skills.

• Field Work: During the upcoming camp at Cape Conran, students will collect data via GPS and input it into a GIS to experience the full data workflow firsthand.

Questions and Discussion

• Pre-Lecture Queries: Students were asked to consider five questions regarding their baseline knowledge of mapping and spatial data.

• Revision Content: A quiz related to this material is available on the unit site, and students are encouraged to review the provided video explaining GIS mechanics in further detail.