I am collecting some potential abiotic factors for determining the most important risk factor(s) associated with the infestation of one of the Lepidopteran insect pests in vineyards. One of the potential factors that I am considering is 'proximity to a forest', assuming that wild vines might contribute to vineyard infestations. I am planning to use google maps/google earth to measure the distance, however, I am not sure what the best way to measure would be. Could I average the perpendicular distances between forest edge and vineyard edge taken at three different points on each side? Is there any standard method that researchers have been following?