Use of a Geographic Information System to represent the spatial distribution of chemical or organic compounds according to the type of compartments in an organism. Example of the distribution of the concentration of non-structural carbohydrates in a tree

Abstract

The management of spatial data and their geographical representation has developed thanks to Geographical Information System (GIS). This article proposes to use the functionalities of these tools to create an illustration in order to spatially represent the intensity of a process or the distribution of a compound within a living organism (such as aerial and undergrounds parts, organs of different ages …). This task is not easy because no specific tools is available. This paper presents a method based on ArcGIS GIS software and R GIS libraries to realize this information representation using a vector type information layer (division into distinct entities which is opposed to the raster type which represents space in a regular mesh). Technically, the proposed approach consists of 1) using a GIS (ArcGIS) to vectorize an image representing the organism, then 2) producing an illustration from the vector layer created according to the desired division. More specifically, the image chosen to represent the organism under study is vectorised into polygon-type objects corresponding to compartments of interest of the organism. Finally, the representation of the intensity of the phenomenon according to the different compartments is accomplished using two softwares, ArcGIS and the GIS libraries of the free statistical software R. This second one has the advantage, once the shape file is created, of being able to be implemented in a script for R data analysis, a software widely used in the scientific community. This second approach allowed, in the example presented in this article, to represent the distribution of nitrogen concentrations or carbohydrate reserves in the different compartments of a beech tree at different dates and subjected to contrasting treatments.