Residue spread mapping

A system for mapping the distribution of residue material in an environment, the system comprising:

• an agricultural machine operable in the environment, the agricultural machine comprising a spreader tool;
• at least one sensor mounted in a sensing arrangement to the agricultural machine;
• a grid-based map of a global distribution of the residue material in the environment, wherein the grid-based map comprises a plurality of cells, each of the plurality of cells corresponding to predefined sub-regions of the environment and having a value representative of a measure of the residue material spread within the corresponding predefined sub-regions;
• and at least one controller configured to:
• receive sensor data from the at least one sensor indicative of the residue material spread by the spreader tool of the agricultural machine;
• determine, from the sensor data, a local distribution of the residue material associated with the spreader tool;
• and
• update the grid-based map of the global distribution of the residue material in the environment based on the local material distribution determined from the sensor data and a location of the agricultural machine, the grid-based map being updated by incrementing the value of at least one of the plurality of cells by a predetermined amount for each determination that the residue material has been spread within the corresponding predefined sub-regions of the environment.