8 The Global Food System and Its Spatial Implications
8.1 Introduction
The global food system is a complex network that connects producers, consumers, and various intermediaries across vast distances. Its spatial implications are profound, influencing everything from agricultural production patterns to food distribution networks and access to resources. This chapter examines the spatial dimensions of the global food system, exploring how geography shapes the production, distribution, and consumption of food on a global scale. By understanding these spatial dynamics, we can better address the challenges of food security, sustainability, and equity in the global food system.
8.2 The Global Food System and Its Spatial Implications
The global food system is characterized by its spatial complexity, with food production, processing, distribution, and consumption often occurring in different parts of the world. This spatial separation has significant implications for food security, environmental sustainability, and economic development.
This section will explore key aspects of the global food system’s spatial implications, including: - Agricultural Production Patterns: How geography influences where different crops are grown, including the role of climate, soil, and water availability. - Global Food Distribution Networks: The logistics of moving food from producers to consumers across vast distances, including the impact of transportation infrastructure and trade policies. - Food Access and Inequality: How spatial factors contribute to disparities in food access, with some regions experiencing food abundance while others face scarcity.
8.3 Using UAV Data for Agricultural Mapping and Analysis
Unmanned Aerial Vehicles (UAVs), commonly known as drones, have revolutionized agricultural mapping and analysis. By providing high-resolution, real-time data, UAVs enable farmers and researchers to monitor crop health, assess land use, and optimize agricultural practices with unprecedented precision.
This section will discuss the use of UAV data in agricultural mapping, including: - The Advantages of UAVs: The benefits of using UAVs for agricultural mapping, such as high-resolution imagery, cost-effectiveness, and the ability to cover large areas quickly. - Applications of UAV Data: How UAV data is used for various agricultural purposes, including crop monitoring, soil analysis, irrigation management, and precision farming. - Integration with GIS: The role of Geographic Information Systems (GIS) in processing and analyzing UAV data, enabling more informed decision-making in agriculture.
8.4 Case Study: Global Agriculture and UAV-Based Mapping
To illustrate the application of UAV data in understanding the global food system, this chapter includes an original case study on global agriculture and UAV-based mapping.
- Global Agriculture and UAV-Based Mapping: This case study will examine how UAVs are being used to map agricultural activities in different parts of the world. The study will focus on the spatial analysis of crop health, land use patterns, and the impact of climate change on agriculture. It will also explore how UAV-based mapping can improve food security by providing more accurate data for decision-making at the farm and policy levels.
8.5 Conclusion
The spatial dimensions of the global food system are critical to understanding how food is produced, distributed, and consumed across the world. By examining agricultural production patterns, food distribution networks, and the use of UAV data in agricultural mapping, this chapter provides insights into the challenges and opportunities of the global food system. The case study on global agriculture and UAV-based mapping demonstrates the practical applications of spatial analysis in enhancing food security and sustainability. As the global food system continues to evolve, the ability to analyze and interpret spatial data will be essential for addressing the complex issues of food production, distribution, and access in a changing world.
8.6 Exercise: Service Area Analysis Using Openrouteservice in QGIS
In this hands-on section, we will explore how to perform Service Area Analysis using the Openrouteservice (ORS) Tools Plugin in QGIS. Service area analysis is commonly used in urban planning and accessibility studies to determine areas that can be served from specific locations based on distance or travel time. For instance, fire stations, hospitals, or public transport stations often rely on such analyses to determine their service reach.
We will use the Openrouteservice API and data from the Kochi Metro Rail Limited (KMRL) to determine areas that can be reached within a 15-minute walking distance from metro stations in Kochi, India.
Objectives:
- Learn how to use the ORS Tools Plugin for service area analysis.
- Load and process General Transit Feed Specification (GTFS) transit feed data.
- Visualize walking service areas using isochrones.
Step 1: Data Setup and Plugin Installation
Download the Required Data
- For this exercise, we will use Kochi Metro Rail Limited (KMRL) GTFS data, which contains information about metro stops and routes in Kochi, India.
- You can request this data from the KMRL Open Data portal or download it directly from the link below:
Sign up for Openrouteservice and Get an API Key
- Openrouteservice (ORS) is a web service providing routing algorithms using OpenStreetMap (OSM) data. It is free but requires an API key.
- To get your API key:
- Visit the Openrouteservice Sign Up page.
- Create an account, activate it, and request an API key.
- Once your account is activated, go to your dashboard and create a Free Token named ORS Tools QGIS.
- Copy the API key provided.
Install the ORS Tools Plugin
- Open QGIS and go to Plugins > Manage and Install Plugins.
- Search for ORS Tools, install it, and close the dialog.
Configure the ORS API Key
- Go to Web > ORS Tools > Provider Settings.
- Expand the openrouteservice section and paste the API key you copied into the API Key text box.
- Click OK to save the settings.
Step 2: Loading and Preparing the Data
Unzip and Explore the GTFS Data
- Unzip the KMRL-Open-Data.zip file to a folder on your computer.
- Inside, you’ll find multiple text files. Of these, two are important:
- shapes.txt: Contains points representing the physical paths of the metro routes.
- stops.txt: Contains the locations of metro stops.
Load the shapes.txt and stops.txt Files into QGIS
- Click the Open Data Source Manager button in QGIS (yellow database icon).
- Switch to the Delimited Text tab, and load the shapes.txt file by selecting CSV (comma separated values) as the format.
- Similarly, load the stops.txt file. These files contain geographic data in tabular form, which will now be displayed as point layers in QGIS.
Convert Points to Metro Line Tracks
- The shapes layer contains points representing the metro lines, but we need to convert them to line features to visualize the paths.
- Go to Processing > Toolbox and search for the Points to Path tool under Vector creation.
- In the Points to Path dialog:
- Set shapes as the input point layer.
- Use the shape_id field for the Path group expression (each metro route has a unique shape_id).
- Use shape_pt_sequence as the Order expression to ensure the points are connected in the correct order.
- Click Run. A new layer representing the metro lines will be added to the map.
Step 3: Performing the Service Area Analysis
Set Up the Service Area Analysis Using ORS Tools
- Now that the metro station and line data are loaded, we will calculate areas within 15 minutes of walking distance from each metro stop.
- Go to Processing > Toolbox and search for Isochrones from Layer under ORS Tools.
Configure the Isochrone Tool
- In the Isochrones From Layer dialog:
- Set stops as the Input Point Layer (this is the layer with the metro stations).
- Use stop_id as the Input Layer ID Field.
- Choose foot-walking as the Travel mode.
- Set time as the Dimension and enter 15 minutes as the travel time range.
- Click Run.
Note: The Openrouteservice API allows up to 20 requests per minute. If you have more than 20 points, the tool will process 20 points at a time and continue automatically.
- In the Isochrones From Layer dialog:
Step 4: Visualizing the Results
Add an OpenStreetMap Basemap
- To better understand the service area polygons, we’ll add a basemap for context.
- In the Browser Panel, scroll down to XYZ Tiles > OpenStreetMap and drag the OSM Standard layer onto the map.
Style the Service Area Polygons
- Once the Isochrones layer is added to QGIS, it will display polygons representing areas within 15 minutes of walking distance from each metro stop.
- Open the Layer Styling Panel and use a color ramp to style the polygons. You can also adjust the transparency to better visualize the basemap underneath.
- The polygons will be irregular in shape because the service area is based on actual road networks, rather than straight-line distances.
Step 5: Merging the Isochrone Polygons
Merge Isochrone Polygons into a Single Service Area
- We need to merge individual polygons to create a single polygon representing the areas accessible from the metro system within a 15-minute walk.
- Go to Processing > Toolbox and search for the Dissolve tool under Vector geometry.
- In the Dissolve dialog:
- Select the Isochrones layer as the input.
- Save the output as 15min_isochrone.gpkg and click Run.
Final Visualization
- A new Dissolved layer will be added to the map, showing the entire service area that can be reached within 15 minutes from any metro station.
- You can style this layer for better visualization and transparency to see the underlying basemap and metro lines.
Conclusion
In this tutorial, you learned how to perform a Service Area Analysis using the Openrouteservice (ORS) Tools Plugin in QGIS. We calculated the areas reachable within a 15-minute walking distance from metro stations in Kochi, India, and created a final service area polygon. These techniques can be applied to various scenarios, such as public transit planning, emergency services, or accessibility studies.
Extensions of this analysis could include adding other modes of transport (e.g., buses) or calculating service areas for multiple travel modes, such as by car, bicycle, or foot.