This paper proposes a new model based on optimal transport theory that provides both a local and global measure of access to primary care. We extend a previously introduced OT-based spatial heterogeneity index designed to analyse spatial disparities in electoral results. The method allows us to identify shortage areas and determine geographically where additional general practitioners (GPs) should be located in order to maximize access to physicians. The model has significant policy implications given that it enables policymakers to target areas in need to implement incentives to attract new physicians. Thus, it helps avoid a concentration of physicians in some areas and help also to design a better distribution of physician across areas. To illustrate our method, we apply our model to Occitanie, the second-largest region in metropolitan France, which displays sufficient spatial heterogeneity for our purposes.