Widely strewn resources have made organizations engrossed to know not only who, when and from where but also for what purpose an access request has been made to use the organization resources. So a flexible model for role-based access control that support the enforcement and revocation of context aware policies is needed; that not only consider temporal and location but also purposes in order to make access control decisions. In this article, we have presented contextual model that mainly rely on the role-based access control models by keeping in mind the notion of purpose. We introduce spatial purpose roles and spatial purposes, their semantics and provide core model of proposed Contextual Role-Based Access Control Model (C-RBAC) for access control. We emphasize that the privacy protection cannot be easily achieved by traditional access control models because it focuses only on which user is performing what operation on what object. By introducing our model, we show how C-RBAC can make use of purpose oriented roles to make access control decisions which is based on which user can perform what operation on which object with what purpose.