1. A method of preparing a layout file defining features to be created via a photolithographic process for optical and process correction, comprising: reading at least a portion of a file defining one or more features to be created; fragmenting the one or more features into a number of edge fragments; defining an initial simulation site associated with a selected one of the edge fragments; using a computer, estimating an image intensity at the initial simulation site; and adjusting the position of the initial simulation site associated with the selected one of the edge fragments based on the estimated image intensity, wherein the adjusting comprises moving the position of the initial simulation site to a new position on the selected one of the edge fragments.