To evaluate boom behaviour, a software was developed to simulate ground spray distributions knowing the sprayer boom movements. To validate this software, ground spray distributions were measured and analysed by spraying a black dye (Nigrosin WLF) on large pre-pasted wallpaper and by measuring the deposit with image analysis. The simulated results were compared with tests made in laboratory conditions. A conveyor with a shaking platform was built to study the dynamic effect and boom movement influence. Several mathematical tools based on statistics, image analysis and signal processing were used to test the validity of the model. Moreover, tests were processed in field conditions by driving a sprayer over a bump, measuring boom movements and spray distributions. The results showed that both in laboratory conditions and in field conditions, the dynamic spray model provided a satisfactory description of the global spray distribution from field sprayers. This mathematical approach is then a useful method to estimate quickly the ground spray distribution and thus boom behaviour