Title
A Comparison between Standard and Functional Clustering Methodologies: Application to Agricultural Fields for Yield Pattern Assessment.
Abstract
The recognition of spatial patterns within agricultural fields, presenting similar yield potential areas, stable through time, is very important for optimizing agricultural practices. This study proposes the evaluation of different clustering methodologies applied to multispectral satellite time series for retrieving temporally stable (constant) patterns in agricultural fields, related to within-field yield spatial distribution. The ability of different clustering procedures for the recognition and mapping of constant patterns in fields of cereal crops was assessed. Crop vigor patterns, considered to be related to soils characteristics, and possibly indicative of yield potential, were derived by applying the different clustering algorithms to time series of Landsat images acquired on 94 agricultural fields near Rome (Italy). Two different approaches were applied and validated using Landsat 7 and 8 archived imagery. The first approach automatically extracts and calculates for each field of interest (FOI) the Normalized Difference Vegetation Index (NDVI), then exploits the standard K-means clustering algorithm to derive constant patterns at the field level. The second approach applies novel clustering procedures directly to spectral reflectance time series, in particular: (1) standard K-means; (2) functional K-means; (3) multivariate functional principal components clustering analysis; (4) hierarchical clustering. The different approaches were validated through cluster accuracy estimates on a reference set of FOIs for which yield maps were available for some years. Results show that multivariate functional principal components clustering, with an a priori determination of the optimal number of classes for each FOI, provides a better accuracy than those of standard clustering algorithms. The proposed novel functional clustering methodologies are effective and efficient for constant pattern retrieval and can be used for a sustainable management of agricultural fields, depending on farming systems and environmental conditions in different regions.
Year
DOI
Venue
2018
10.3390/rs10040585
REMOTE SENSING
Keywords
Field
DocType
clustering methods,Landsat time series,high-resolution maps,agricultural fields
Hierarchical clustering,Pattern recognition,Multivariate statistics,A priori and a posteriori,Multispectral image,Remote sensing,Normalized Difference Vegetation Index,Artificial intelligence,Geology,Cluster analysis,Spatial ecology,Principal component analysis
Journal
Volume
Issue
ISSN
10
4
2072-4292
Citations 
PageRank 
References 
0
0.34
13
Authors
7
Name
Order
Citations
PageRank
Simone Pascucci14812.85
Maria Francesca Carfora2195.54
Angelo Palombo3204.69
Stefano Pignatti48016.28
Raffaele Casa56511.75
Monica Pepe68815.15
Fabio Castaldi741.46