The question of finding an appropriate scale to study adaptation emerged only recently in landscape genomics, while in landscape ecology its components (extent and resolution or grain) have been addressed in many papers. In fact, in landscape genetics only a couple of studies have considered different extents to study adaptation but the spatial resolution of environmental variables was not considered. However, when these variables are derived from digital elevation models (DEMs), the question of resolution becomes crucial. Here we used a signal processing generalization technique to produce DEMs a multiple scales allowing for a continuous representation of the landscape. We then investigated the adaptive response of the buckler mustard (Biscutella laevigata L.) to solar radiation with the help of environmental variables derived from these DEMs.