Soil is the outside layer of Earth. It is a made up of living organisms, gases, minerals, and organic matter. Knowing what minerals are in the soil helps to understand how it was made and where it came from. Geochemists test soil samples using different methods to see the spread of elements and minerals across the country. 17 different elements and properties were mapped on a 1:100,000 scale (1cm on the map relates to a distance of 1km). An area of over 18,699 km2 or 26.5% of country was surveyed. A total of 5643 deeper topsoil samples were collected between 2011 and 2017. In G1 and G3, one sample taken within a 2km by 2km grid. In the G6 Dublin and Galway periurban areas, one sample was taken within a 1km by 1km grid. The data measures changes in the strength of a number of elements in two ways. Also tested were loss on ignition, which tells us the amount of organic carbon in the soil and pH, which shows how acid or basic the soils are. The types of elements can point to where they came from and geological history of soils. Their parent material is called as a source rock. This is a raster dataset. Data is presented in form of an image and color scales are used to show the different strengths of the elements. Raster data stores information in a cell-based manner and consists of a matrix of cells (or pixels) organised into rows and columns. The format of the raster is a grid. The grid cell size is 250 m which means that each cell (pixel) represents an area on the ground that is 250 meters across. The grid also contains location information. The Tellus survey is a national airborne geophysical and ground geochemical mapping project managed by the Geological Survey Ireland.