A method includes determining topographic information of a substrate for use in a lithographic imaging system, determining or estimating, based on the topographic information, imaging error information for a plurality of points in an image field of the lithographic imaging system, adapting a design for a patterning device based on the imaging error information. In an embodiment, a plurality of locations for metrology targets is optimized based on imaging error information for a plurality of points in an image field of a lithographic imaging system, wherein the optimizing involves minimizing a cost function that describes the imaging error information. In an embodiment, locations are weighted based on differences in imaging requirements across the image field.