Probabilistic Tracking of Annual Cropland Changes over Large, Complex Agricultural Landscapes Using Google Earth Engine
Cropland expansion is expected to increase across sub-Saharan African (SSA) countries in the next thirty years to meet growing food needs across the continent. These land transformations will have cascading social and ecological impacts that can be monitored using novel Earth observation techniques...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-09-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/14/19/4896 |
| _version_ | 1797477125444337664 |
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| author | Sitian Xiong Priscilla Baltezar Morgan A. Crowley Michael Cecil Stefano C. Crema Eli Baldwin Jeffrey A. Cardille Lyndon Estes |
| author_facet | Sitian Xiong Priscilla Baltezar Morgan A. Crowley Michael Cecil Stefano C. Crema Eli Baldwin Jeffrey A. Cardille Lyndon Estes |
| author_sort | Sitian Xiong |
| collection | DOAJ |
| description | Cropland expansion is expected to increase across sub-Saharan African (SSA) countries in the next thirty years to meet growing food needs across the continent. These land transformations will have cascading social and ecological impacts that can be monitored using novel Earth observation techniques that produce datasets complementary to national cropland surveys. In this study, we present a flexible Bayesian data synthesis workflow on Google Earth Engine (GEE) that can be used to fuse optical and synthetic aperture radar data and demonstrate its ability to track agricultural change at national scales. We adapted the previously developed Bayesian Updating of Land Cover (Unsupervised) algorithm (BULC-U) by integrating a shapelet and slope thresholding algorithm to identify the locations and dates of cropland expansion and implemented a tiling scheme to allow the processing of large volumes of imagery. We apply this approach to map annual cropland change from 2000 to 2015 for Zambia (750,000 km<sup>2</sup>), a country that is experiencing rapid growth in agricultural land. We applied our cropland mapping approach to a time series of unsupervised classifications developed from Landsat 5, 7, 8, Sentinel-1, and ALOS PALSAR within 1476 tiles covering Zambia. The annual cropland changes maps reveal active cropland expansion between 2000 to 2015 in Zambia, especially in the Southern, Central, and Eastern provinces. Our accuracy assessment estimates that we have identified 27.5% to 69.6% of the total cropland expansion from 2000 to 2015 in Zambia (commission errors between 6.1% to 37.6%), depending on the slope threshold. Our results demonstrate the usefulness of Bayesian data fusion and shapelet, slope-based thresholding to synthesize optical and synthetic aperture radar for monitoring agricultural changes in situations where training data are scarce. In addition, the annual cropland maps provide one of the first spatially continuous, annually incremented accounts of cropland growth in this region. Our flexible, cloud-based workflow using GEE enables multi-sensor, national-scale agricultural change monitoring at low cost for users. |
| first_indexed | 2024-03-09T21:13:11Z |
| format | Article |
| id | doaj.art-9849b09adac9409cb615ceab406d4443 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-09T21:13:11Z |
| publishDate | 2022-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-9849b09adac9409cb615ceab406d44432023-11-23T21:40:27ZengMDPI AGRemote Sensing2072-42922022-09-011419489610.3390/rs14194896Probabilistic Tracking of Annual Cropland Changes over Large, Complex Agricultural Landscapes Using Google Earth EngineSitian Xiong0Priscilla Baltezar1Morgan A. Crowley2Michael Cecil3Stefano C. Crema4Eli Baldwin5Jeffrey A. Cardille6Lyndon Estes7Graduate School of Geography, Clark University, Worcester, MA 01610, USAGraduate School of Geography, Clark University, Worcester, MA 01610, USADepartment of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, CanadaGraduate School of Geography, Clark University, Worcester, MA 01610, USAClark Labs, Clark University, Worcester, MA 01610, USAGraduate School of Geography, Clark University, Worcester, MA 01610, USADepartment of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, CanadaGraduate School of Geography, Clark University, Worcester, MA 01610, USACropland expansion is expected to increase across sub-Saharan African (SSA) countries in the next thirty years to meet growing food needs across the continent. These land transformations will have cascading social and ecological impacts that can be monitored using novel Earth observation techniques that produce datasets complementary to national cropland surveys. In this study, we present a flexible Bayesian data synthesis workflow on Google Earth Engine (GEE) that can be used to fuse optical and synthetic aperture radar data and demonstrate its ability to track agricultural change at national scales. We adapted the previously developed Bayesian Updating of Land Cover (Unsupervised) algorithm (BULC-U) by integrating a shapelet and slope thresholding algorithm to identify the locations and dates of cropland expansion and implemented a tiling scheme to allow the processing of large volumes of imagery. We apply this approach to map annual cropland change from 2000 to 2015 for Zambia (750,000 km<sup>2</sup>), a country that is experiencing rapid growth in agricultural land. We applied our cropland mapping approach to a time series of unsupervised classifications developed from Landsat 5, 7, 8, Sentinel-1, and ALOS PALSAR within 1476 tiles covering Zambia. The annual cropland changes maps reveal active cropland expansion between 2000 to 2015 in Zambia, especially in the Southern, Central, and Eastern provinces. Our accuracy assessment estimates that we have identified 27.5% to 69.6% of the total cropland expansion from 2000 to 2015 in Zambia (commission errors between 6.1% to 37.6%), depending on the slope threshold. Our results demonstrate the usefulness of Bayesian data fusion and shapelet, slope-based thresholding to synthesize optical and synthetic aperture radar for monitoring agricultural changes in situations where training data are scarce. In addition, the annual cropland maps provide one of the first spatially continuous, annually incremented accounts of cropland growth in this region. Our flexible, cloud-based workflow using GEE enables multi-sensor, national-scale agricultural change monitoring at low cost for users.https://www.mdpi.com/2072-4292/14/19/4896agriculturechange detectionBayesian fusionZambiaGoogle Earth Engine |
| spellingShingle | Sitian Xiong Priscilla Baltezar Morgan A. Crowley Michael Cecil Stefano C. Crema Eli Baldwin Jeffrey A. Cardille Lyndon Estes Probabilistic Tracking of Annual Cropland Changes over Large, Complex Agricultural Landscapes Using Google Earth Engine Remote Sensing agriculture change detection Bayesian fusion Zambia Google Earth Engine |
| title | Probabilistic Tracking of Annual Cropland Changes over Large, Complex Agricultural Landscapes Using Google Earth Engine |
| title_full | Probabilistic Tracking of Annual Cropland Changes over Large, Complex Agricultural Landscapes Using Google Earth Engine |
| title_fullStr | Probabilistic Tracking of Annual Cropland Changes over Large, Complex Agricultural Landscapes Using Google Earth Engine |
| title_full_unstemmed | Probabilistic Tracking of Annual Cropland Changes over Large, Complex Agricultural Landscapes Using Google Earth Engine |
| title_short | Probabilistic Tracking of Annual Cropland Changes over Large, Complex Agricultural Landscapes Using Google Earth Engine |
| title_sort | probabilistic tracking of annual cropland changes over large complex agricultural landscapes using google earth engine |
| topic | agriculture change detection Bayesian fusion Zambia Google Earth Engine |
| url | https://www.mdpi.com/2072-4292/14/19/4896 |
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