Title
Understanding the Requirements for Surveys to Support Satellite-Based Crop Type Mapping: Evidence from Sub-Saharan Africa
Abstract
This paper provides recommendations on how large-scale household surveys should be conducted to generate the data needed to train models for satellite-based crop type mapping in smallholder farming systems. The analysis focuses on maize cultivation in Malawi and Ethiopia, and leverages rich, georeferenced plot-level data from national household surveys that were conducted in 2018-20 and integrated with Sentinel-2 satellite imagery and complementary geospatial data. To identify the approach to survey data collection that yields optimal data for training remote sensing models, 26,250 in silico experiments are simulated within a machine learning framework. The best model is then applied to map seasonal maize cultivation from 2016 to 2019 at 10-m resolution in both countries. The analysis reveals that smallholder plots with maize cultivation can be identified with up to 75% accuracy. Collecting full plot boundaries or complete plot corner points provides the best quality of information for model training. Classification performance peaks with slightly less than 60% of the training data. Seemingly little erosion in accuracy under less preferable approaches to georeferencing plots results in the total area under maize cultivation being overestimated by 0.16-0.47 million hectares (8-24%) in Malawi.
Year
DOI
Venue
2021
10.3390/rs13234749
REMOTE SENSING
Keywords
DocType
Volume
agriculture, maize, crop type mapping, Sentinel-2, household surveys, training data, Malawi, Ethiopia
Journal
13
Issue
Citations 
PageRank 
23
0
0.34
References 
Authors
0
5
Name
Order
Citations
PageRank
George Azzari100.34
Shruti Jain200.34
Graham Jeffries300.34
Talip Kilic400.34
Siobhan Murray500.34