This course introduces the following topics:
What is Geospatial Analysis?
We start the course with defining what geospatial analysis is. Understanding the nature of geospatial analysis is essential for constructing and recognizing geospatial questions. The related field and technology, GIS (Geographic Information Science/System) will also be introduced.
Horizontal and Vertical Reference Systems, Map Projections
Horizontal and vertical positions on or near the surface of the Earth are expressed as numeric measurements off a reference system, or, a datum. Different horizontal and vertical datums exist to serve different regions of the world and the different purposes.
Map projections are used to convert horizontal position measurements referencing a datum, a 3D reference system, to a 2D surface to support the use of geographic data in the 2D environment, e.g. paper, computer screen. All map projections introduce distortions. We will learn the types of distortions introduced by map projections, and ways to minimize the distortions for an area of interest
Although topics in datums and map projections may seem dry and irrelevant to the great maps you have seen, they are essential knowledge for anyone who creates or uses geospatial data – geospatial data scientists, cartographers, geospatial app developers, GIS users, GNSS (Global Navigation Satellite System) users and map readers, to name a few.
GIS Data Models
We continue with topics on how to encapsulating the world in a computer. Conceptual models for storing objects with identifiable boundary (trees, streets, parks) and phenomena with no clearly defined boundary (temperature, CO2 concentration in the atmosphere) will be introduced, as well as the common GIS data formats that implements these conceptual data models and the technical details you need to know to work with GIS data.
Data Display and Cartography (1)
After the foundation building, we take a look at usually the first task after adding a GIS data file in software – displaying the data. For data exploration, effective data display, or, data visualization, helps revealing geospatial patterns, outliers or associations. For map making, it enables us create maps that effectively communicate our findings. For map reading, it equips us with critical eyes for common mistakes people make in creating maps.
Topics introduced includes levels of measurements, data classifications, the uses of visual variables, and common quantitative map types.
Geospatial Analysis Methods
Among the various ways of deriving information from geographic data, we introduce the following:
- Data query based on attributes (e.g. population density, land use types) and spatial relationships (e.g. lands in City of Northfield that are on floodplains).
- Basic analysis methods with vector data, including geometric properties (e.g. compactness of congressional districts, areas of wildlife habitats), Buffering, Overlay, Dissolve, and distance measurements.
- Basic analysis methods with raster data, including local, neighborhood, zonal and global operations, and map algebra.
- Cartographic modeling, a set of interacting, ordered map operations that act on raw data, as well as derived and intermediate map data, to simulate a spatial decision-making process (Tomlin, 1990). The basic methods introduced earlier in the class and those later can all be applied in the cartographic modeling process.
- Basic terrain analysis.
- Least-cost path analysis.
- Spatial statistics. We will discuss why conventional statistics do not work for geospatial data and use two spatial statistics to illustrate how spatial statistics address the challenges. Simple descriptive spatial statistics will be introduced.
Pitfalls in Geospatial Analysis
We conclude the topics in geospatial analysis with pitfalls in geospatial analysis – the Modifiable Areal Unit Problem (MAUP), the Ecological Fallacy, and Edge effects.
We hope the topics introduced in geospatial analysis help you understand what thinking spatially is in analyzing geospatial data and consuming geospatial information.
Cartography (2) – Map Design
We end the course with a second visit to Cartography – the science and arts of map making. This time we look at map layout design. The results of geospatial analysis are often communicated with maps. It is therefore important for us to know how to make maps that effectively convey our findings. This course introduces only the very basics of Cartography. Interested students should consider taking courses in Cartography.
