Landmines remain in conflict areas for decades after the end of hostilities. Their suspected presence renders vast tracts of land unusable for development and agriculture causing significant psychological and economical damage. Landmine removal is a slow and dangerous process. Compounding the difficulty, modern landmines use minimal amounts of metallic content making them very hard to detect and to distinguish from other metallic debris (such as bullet shells, wires, etc.) frequently present in post-combat areas. Recent research has demonstrated that the accuracy of landmine detection can be improved if deminers try to mentally represent the shape of the area where the metal detector's response gets triggered. Despite similar amounts of metallic content, mines and clutter results in areas of different shapes. Building on these findings, we have created a visual decision support tool that presents the deminer with an explicit visualization of the shapes of these response areas. The results of our study demonstrate that this tool significantly improves novice deminers' detection rates and it improves the localization accuracy.