AlvarAalto 1.0 β Alvar Aalto is a cloud-based application for the reconnaissance and mapping of Ailanthus altissima. The system combines a GIS-prepared training and control dataset (Aalto) with the Google Earth Engine processing script (Alvar), which retrieves multispectral and thermal satellite imagery, extracts key spectral and topographic features, and performs large-scale classification over an area of interest using established machine-learning methods. The output consists of a classified raster map and vectorized polygons of potential A. altissima presence, supporting the assessment of tree invasion patterns. The Alvar algorithm is based on the assumption that Sentinel-2 imagery, although only barely sufficient in resolution, can still be exploited to detect the presence of such trees.