Chapter 16

Geographical Information Systems in Agriculture

GIS Visualization and Mapping

GIS visualization and mapping refer to the process of transforming geographic data into visual formats (like maps, charts, and 3D models) to reveal patterns, trends, and relationships in space. Maps are essential components of all GISs. For instance, maps constitute both the input and output of a GIS. GIS mapping refers to creating visual representations of spatial data using GIS technology. These maps help analyze, interpret, and visualize geographic relationships, patterns, and trends. GIS mapping integrates data layers with geographic coordinates, allowing users to explore spatial information interactively.

Key Components

Geographic information systems (GIS) visualization and mapping involve representing and analyzing geographic data in a visual format. This process relies on a combination of components working together to transform raw data into informative maps and visualizations. These components can be broadly categorized as follows in Table 16.9.

Types of GIS Maps

GIS maps are thematic visualizations that help analyze, interpret, and present spatial data. Each type of GIS map serves a unique purpose depending on the data type, goal, and analysis required.

Thematic Maps

Thematic maps in GIS are designed to highlight specific attributes or themes related to spatial data (Figure 16.4). In agriculture, these maps are powerful tools for visualizing crop types, productivity, soil quality, water availability, and more—enabling better planning, monitoring, and decision-making. A thematic map displays the spatial distribution of one specific variable or theme. They focus on a particular "theme" or set of related data, such as:

Heat Maps. Heat maps in GIS are used to visualize the intensity, density, or concentration of agricultural data across a geographic area (Figure 16.5). They are excellent tools for identifying patterns and anomalies in farm-related variables like crop health, rainfall, pest outbreaks, and more.
Dot Density Maps. Dot density maps are a type of thematic map that uses dots to visually represent the density or distribution of a particular phenomenon, like agricultural production (Figure 16.6). Each dot represents a specific quantity of the phenomenon, such as 5,000 tons of maize or 1,000 bushels of wheat.
Choropleth Maps. Choropleth maps are a widely used type of thematic map in GIS that use color shading or patterns to represent data values across predefined areas like districts, farms, or administrative zones (Figure 16.7). In agriculture, choropleth maps are incredibly useful for visualizing and analyzing spatial patterns in farm production, soil characteristics, climate variables, and more. A choropleth map assigns colors or patterns to regions based on numerical or categorical data.

Time-Series Maps

A GIS time-series map for agriculture displays spatial data collected over various time intervals. They combine geographic information with a timeline, allowing users to visualize and analyze how agricultural phenomena change across space and time. This could be anything from tracking crop growth over a season to monitoring soil moisture levels over several years.

Topographic Maps

Topographic maps, which visually represent land elevation through contour lines, are valuable tools in agriculture (Figure 16.8). They help farmers understand how topography influences factors like soil health, water flow, and crop yield, enabling more efficient and effective agricultural practices. The effects of topography on soil properties and crop growth and yield depend on soil type and depth, climate, cropping system, and management practices.

Interactive Web Maps

Interactive web maps in agriculture are online mapping applications that allow users to visualize, analyze, and interact with agricultural data, often at a geographic level. They enable users to explore spatial patterns, access detailed information about specific locations, and make informed decisions based on the displayed data. These maps can be used by farmers, researchers, policymakers, and other stakeholders to better understand agricultural trends, manage resources, and improve farming practices.

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