mobile device does not natively accept likewise the initial geo fence e g non supported geo fence may have any of a variety of sizes including sizes larger than a mobile device will accept sizes smaller than a mobile device will accept or other sizes at step 820 the approximation process generates a group of m geo fences whose union approximates the initial geo fence e g non supported geo fence where m is a value greater than or equal to one i e m gt 1 the group of m geo fences may be natively supported by the mobile device 110 such that the geo fences are considered u201c supported geo fences u201d for example as shown in fig9 five circular geo fences e g a group of five supported geo fences 920 924 may approximate the initial geo fence e g non supported geo fence 910 the group of m geo fences may be considered to u201c approximate u201d the initial geo fence based on one or more standards in one implementation the m geo fences may u201c approximate u201d the initial geo fence by their union defining a minimum bounding shape that encloses the initial geo fence in another implementation the m geo fences may u201c approximate u201d the initial geo fence by their union including a given percentage e g 95 of the initial geo fence a.