Zone de Texte: A REVIEW ON GEOMATIC TOOLS FOR ASSESSING, INVENTORYING AND MAPPING ALIEN PLANT INVASIONS IN THE MEDITERRANEAN BASIN Zone de Texte: Each alien plant (population) has to be described in terms of GIS primitives, i.e. point, line, polygon. Zone de Texte: Data Collection Primitives Zone de Texte: Point feature: a single alien plant or a formation/community of alien plants that cover a surface less or equal to 10,000 m2 with a pattern that cannot be described as line feature. When point features are closer than 50 m they may be grouped in a line feature or in a area feature according to their spatial pattern and to the proximity to other features. Line feature (arc): a single alien plant or a formation/community of alien plants distributed mainly on a linear or polylinear axis, with a minimum length of 250 m measured at its main axis and a maximum width of 50 m measured as perpendicular to the main axis. It is mainly used for infestations that follow linear features such as roads, streams, fences and irrigation channels or drainage lines. Area feature (polygon): a formation/community of alien plants covering a surface larger than 10,000 m2, with at least one dimension longer than 50 m.

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