National crop mapping using sentinel-1 time series: A knowledge-based descriptive algorithm

Carole Planque*, Richard Lucas, Suvarna Punalekar, Sebastien Chognard, Clive Hurford, Christopher Owers, Claire Horton, Paul Guest, Stephen King, Sion Williams, Peter Bunting

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Citations (SciVal)
242 Downloads (Pure)

Abstract

National-level mapping of crop types is important to monitor food security, understand environmental conditions, inform optimal use of the landscape, and contribute to agricultural pol-icy. Countries or economic regions currently and increasingly use satellite sensor data for classifying crops over large areas. However, most methods have been based on machine learning algorithms, with these often requiring large training datasets that are not always available and may be costly to produce or collect. Focusing on Wales (United Kingdom), the research demonstrates how the knowledge that the agricultural community has gathered together over past decades can be used to develop algorithms for mapping different crop types. Specifically, we aimed to develop an alterna-tive method for consistent and accurate crop type mapping where cloud cover is quite persistent and without the need for extensive in situ/ground datasets. The classification approach is parcel-based and informed by concomitant analysis of knowledge-based crop growth stages and Sentinel-1 C-band SAR time series. For 2018, crop type classifications were generated nationally for Wales, with regional overall accuracies ranging between 85.8 % and 90.6 %. The method was particularly successful in distinguishing barley from wheat, which is a major source of error in other crop products available for Wales. This study demonstrates that crops can be accurately identified and mapped across a large area (i.e., Wales) using Sentinel-1 C-band data and by capitalizing on knowledge of crop growth stages. The developed algorithm is flexible and, compared to the other methods that allow crop mapping in Wales, the approach provided more consistent discrimination and lower variability in accuracies between classes and regions.

Original languageEnglish
Article number846
Number of pages30
JournalRemote Sensing
Volume13
Issue number5
DOIs
Publication statusPublished - 25 Feb 2021

Keywords

  • Crop type
  • Growth stage
  • Land cover classification
  • SAR
  • Sentinel-1
  • Time series

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