title: Mapping Vineyard Leaf Area Using Mobile Terrestrial Laser Scanners: Should Rows be Scanned On-the-Go or Discontinuously Sampled?
abstract: The leaf area index (LAI) is defined as the one-side leaf area per unit ground area, and is probably the most widely used index to characterize grapevine vigor. However, LAI varies spatially within vineyard plots. Mapping and quantifying this variability is very important for improving management decisions and agricultural practices. In this study, a mobile terrestrial laser scanner (MTLS) was used to map the LAI of a vineyard, and then to examine how different scanning methods (on-the-go or discontinuous systematic sampling) may affect the reliability of the resulting raster maps. The use of the MTLS allows calculating the enveloping vegetative area of the canopy, which is the sum of the leaf wall areas for both sides of the row (excluding gaps) and the projected upper area. Obtaining the enveloping areas requires scanning from both sides one meter length section along the row at each systematic sampling point. By converting the enveloping areas into LAI values, a raster map of the latter can be obtained by spatial interpolation (kriging). However, the user can opt for scanning on-the-go in a continuous way and compute 1-m LAI values along the rows, or instead, perform the scanning at discontinuous systematic sampling within the plot. An analysis of correlation between maps indicated that MTLS can be used discontinuously in specific sampling sections separated by up to 15 m along the rows. This capability significantly reduces the amount of data to be acquired at field level, the data storage capacity and the processing power of computers.
authors.affiliation: Research Group on AgroICT & Precision Agriculture, Department of Agricultural and Forest Engineering, University of Lleida, Rovira Roure 191, Lleida 25198, Spain. igdemo@eagrof.udl.cat.
authors.forename: Ignacio
authors.initials: I
authors.lastname: del-Moral-Martínez
authors.affiliation: Research Group on AgroICT & Precision Agriculture, Department of Agricultural and Forest Engineering, University of Lleida, Rovira Roure 191, Lleida 25198, Spain. jr.rosell@eagrof.udl.cat.|Research Group on AgroICT &amp; Precision Agriculture, Agrotecnio Center, Rovira Roure 191, Lleida 25198, Spain. jr.rosell@eagrof.udl.cat.
authors.forename: Joan R
authors.initials: JR
authors.lastname: Rosell-Polo
authors.affiliation: Research Group on AgroICT & Precision Agriculture, Department of Agricultural and Forest Engineering, University of Lleida, Rovira Roure 191, Lleida 25198, Spain. jcompany@alumnes.udl.cat.
authors.forename: Joaquim
authors.initials: J
authors.lastname: Company
authors.affiliation: Research Group on AgroICT & Precision Agriculture, Department of Agricultural and Forest Engineering, University of Lleida, Rovira Roure 191, Lleida 25198, Spain. rsanz@eagrof.udl.cat.|Research Group on AgroICT &amp; Precision Agriculture, Agrotecnio Center, Rovira Roure 191, Lleida 25198, Spain. rsanz@eagrof.udl.cat.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Sanz
authors.affiliation: Research Group on AgroICT & Precision Agriculture, Department of Agricultural and Forest Engineering, University of Lleida, Rovira Roure 191, Lleida 25198, Spain. aescola@eagrof.udl.cat.|Research Group on AgroICT &amp; Precision Agriculture, Agrotecnio Center, Rovira Roure 191, Lleida 25198, Spain. aescola@eagrof.udl.cat.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Escolà
authors.affiliation: Research Group on AgroICT & Precision Agriculture, Department of Agricultural and Forest Engineering, University of Lleida, Rovira Roure 191, Lleida 25198, Spain. jmv@eagrof.udl.cat.
authors.forename: Joan
authors.initials: J
authors.lastname: Masip
authors.affiliation: Research Group on AgroICT & Precision Agriculture, Department of Environmental and Soil Sciences, University of Lleida, Rovira Roure 191, Lleida 25198, Spain. j.martinez@macs.udl.cat.|Research Group on AgroICT &amp; Precision Agriculture, Agrotecnio Center, Rovira Roure 191, Lleida 25198, Spain. j.martinez@macs.udl.cat.
authors.forename: José A
authors.initials: JA
authors.lastname: Martínez-Casasnovas
authors.affiliation: Research Group on AgroICT & Precision Agriculture, Department of Agricultural and Forest Engineering, University of Lleida, Rovira Roure 191, Lleida 25198, Spain. jarno@eagrof.udl.cat.|Research Group on AgroICT &amp; Precision Agriculture, Agrotecnio Center, Rovira Roure 191, Lleida 25198, Spain. jarno@eagrof.udl.cat.
authors.forename: Jaume
authors.initials: J
authors.lastname: Arnó
mesh_terms: D000383:Agriculture / Q000379:methods*; D000465:Algorithms; D017143:Fuzzy Logic; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D018515:Plant Leaves / Q000502:physiology*; D027843:Vitis / Q000502:physiology*
keywords: LAI; LiDAR; mobile terrestrial laser scanner; precision viticulture; vegetation maps