GDA allows you to create IDW maps for pollution monitoring and mapping The user can collect chemical information over the field and associate them with a specific geographical position. Through an easy and user friendly interface, you can collect and elaborate chemical data directly on your smartphone and use them in a colorfull (Inverse Distance Weighting) IDW map. The app includes also an experimental Voronoi module to create tesselation and subdivide areas in smaller regions as well a statistics module providing also a spatial Kringing semivariance analysis to highlight data correlation over the investigated area.