Mapping Crop Health from Space: How KNUST YouthMappers Used Digital Earth Africa to Support Local Farming

Introduction

Agriculture and technology are increasingly intersecting to solve real-world challenges, especially in food production and sustainability. This blog explores an exciting initiative that demonstrates how Geographic Information Systems (GIS) and satellite data can be used to assess crop health. Led by the KNUST YouthMappers chapter, the project focused on mapping and analyzing farmlands on the Kwame Nkrumah University of Science and Technology (KNUST) campus using the Digital Earth Africa Learning Platform. The goal was to evaluate crop health patterns and understand how satellite data can guide better farming decisions. Before delving into the methods and findings, it's important to reflect on the motivation that inspired this work.

Across Ghana and much of Africa, unpredictable rainfall and soil degradation have become silent threats to sustainable farming. Lettuce and other leafy vegetables, though fast-growing, are extremely sensitive to both drought and excess water. We wanted to see whether the same satellite tools used for continental-scale monitoring could help uncover these subtle stress patterns at a local level, right here at KNUST. Our journey began not just as a class project, but as a question: can youth-led mapping and remote sensing truly make a difference in everyday farming? The answer, as we found, was more complex and more inspiring than we expected.

Project Background

The initiative began when Kingsley, the president of KNUST YouthMappers, completed a course on the Digital Earth Africa platform focused on crop health analysis. Eager to apply his knowledge in a practical setting, he identified the farmlands on KNUST's campus as an ideal case study. The university has a long history of supporting local farmers by providing fertile land for agricultural purposes. These farmlands, known for producing vegetables such as lettuce, cabbage, and spring onions, play an important role in the local food supply chain.

Several factors made these farmlands suitable for our study. The farms are cultivated year-round, which allowed us to monitor crop health across different growing seasons. Their proximity to campus also made data collection efficient and cost-effective. Moreover, the economic and nutritional importance of these farms highlighted the need for consistent health assessments. Beyond the agricultural benefits, the project also provided an excellent opportunity for students to apply GIS and remote sensing tools in a practical, real-world setting.

Located along the eastern edge of the KNUST campus, the farms sit between a small river and a main access road — a natural contrast that later proved essential to our findings. This layout helped us observe how topography and proximity to water or road surfaces can influence vegetation health. The continuous cultivation cycle provided a rare opportunity to compare NDVI trends across both dry and rainy seasons. This revealed how excess rainfall and poor drainage could quietly affect crop vigor — details invisible to the eye but captured clearly through satellite imagery. Beyond the scientific analysis, the project bridged classroom theory and real-world impact. It reminded us that GIS is not just about maps and data, but about supporting farmers, improving food quality, and advancing sustainable agriculture in Ghana.

Assembling the Team

No impactful project succeeds without collaboration. After developing the initial concept, I shared the idea with my executive team, who were immediately excited about its potential. Together, we presented it to the wider KNUST YouthMappers community, and the response was overwhelmingly positive. Many members expressed interest in gaining hands-on experience in GIS and satellite-based analysis. From there, the project naturally grew into a collective effort. Students from geography, agriculture, environmental science, and even chemistry joined in, each bringing a different lens to the same goal. We quickly realized that understanding crop health required more than mapping skills; it needed knowledge about soil, nutrients, and plant behavior too.

To ensure efficiency, we divided the participants into smaller groups, each assigned to specific farmlands. This division made data collection more organized and allowed every team to contribute meaningfully to the project. Some members focused on GPS data collection, others on farmer engagement, and a few took charge of NDVI and GIS processing. This diversity of tasks made everyone feel included and showed how interdisciplinary teamwork could turn technical data into real-world solutions. Looking back, what started as a small mapping exercise became a model for how YouthMappers projects can merge science, technology, and local knowledge, with every student learning something beyond their discipline.

Data Collection Process

The foundation of this project was gathering accurate data from the farmlands. The team developed a structured plan to ensure comprehensive data collection:

• Engagement with Farmers: Three heads of the local farmers were briefed on the study's objectives and potential benefits, gaining their cooperation.

• GPS Mapping: Using GPS Status Saver, each group recorded the coordinates of different farmland plots to accurately map our study area.

• Satellite Data Acquisition: The Digital Earth Africa platform was utilized to retrieve relevant satellite imagery for analysis. Using the Digital Earth Africa Sandbox open data source, each team was able to perform crop health analysis.

Understanding the Digital Earth Africa Platform

Digital Earth Africa is a powerful open-access platform designed to make satellite data accessible and usable for African users. It leverages Sentinel-2 satellite imagery to monitor environmental and agricultural changes over time. One of its key analytical tools is the Normalized Difference Vegetation Index (NDVI), which measures vegetation health by comparing the reflectance of near-infrared and red light. NDVI values range from -1 to 1, with higher values indicating healthier vegetation. This makes NDVI a reliable metric for identifying areas of stress or poor crop performance that might require attention.

The beauty of Digital Earth Africa lies in its simplicity. Even without high-end computers or paid software, students and farmers alike can visualize vegetation patterns, rainfall impact, and seasonal changes directly from open-source satellite data. This made it the perfect tool for a youth-led research project like ours, where learning, access, and impact go hand in hand.

Conducting the Crop Health Analysis

Before heading to the field, our teams received training on how to use the Digital Earth Africa Sandbox platform. Each member created an account and explored the available tools, datasets, and notebooks — particularly the Crop Health Analysis notebook, which became central to our project. This notebook was specifically designed to analyze vegetation health using Sentinel-2 imagery.

Using the farmland coordinates we had collected, we selected the relevant spatial extent and time range for our analysis, focusing on the main growing seasons of KNUST's farmlands. The platform's built-in code allowed us to process the satellite data and compute NDVI values automatically. Once the analysis was complete, we visualized the results in map form, overlaying NDVI values on the farmland boundaries. We then compared the NDVI maps from different months to see how vegetation health changed over time.

A striking pattern emerged: farmlands located close to the small river consistently recorded higher NDVI values (often between 0.7 and 0.9) compared to those near the road, which averaged around 0.4 to 0.5. This suggested that access to steady soil moisture supported healthy crops near the river, while compaction, runoff, and dust near the roadside may have contributed to reduced vegetation vigor.

Interpreting Results and Making Recommendations

After visualizing and interpreting the NDVI data, our team developed interview guides to engage farmers and discuss the findings. This interaction helped us link the observed NDVI patterns to on-the-ground realities, such as irrigation practices and soil conditions. Areas with low NDVI values were often associated with factors like poor drainage or inconsistent watering schedules. Based on these insights, we proposed practical interventions such as adjusting irrigation, applying organic fertilizers, and adopting pest control measures to enhance crop health.

This integration of satellite-based analysis with farmer knowledge provided a holistic understanding of the farmlands' health. It also demonstrated how GIS and remote sensing can support data-driven agricultural decision-making at a local level.

Conclusion

This project showcased how youth-led innovation and open-access technology can work together to improve agriculture. By combining field data collection, satellite imagery, and digital analysis, we were able to generate actionable insights for farmers while enhancing our technical skills as students. The experience reinforced the importance of using geospatial tools for sustainable agriculture and food security. Ultimately, the KNUST YouthMappers' crop health initiative stands as a testament to how education, collaboration, and technology can come together to make a tangible impact on local communities.

Authors

Isaac Kingsley Arthur-Gaisie is a recent Geography graduate from the Kwame Nkrumah University of Science and Technology (KNUST) and the immediate past President of the KNUST YouthMappers Chapter. He joined YouthMappers in 2021 and has since been deeply involved in promoting open mapping, GIS education, and community-based geospatial projects in Ghana. Kingsley is passionate about using geospatial technology to drive sustainable development and create data-driven solutions for real-world challenges.

Asase-Abotsi Helena Elikem is a Geography and Rural Development graduate from Kwame Nkrumah University of Science and Technology (KNUST) and an active member of the KNUST YouthMappers Chapter. Passionate about rural development, she loves using GIS, research, and writing to explore solutions for real community challenges. At YouthMappers, Helena contributes to mapping projects and research initiatives that turn data into actionable insights for sustainable development.