In this paper an improved version of the graded precision localization algorithm GRADELOC, calledIGRADELOC is proposed. The performance of GRADELOC is dependent on the regions formed by theoverlapping radio ranges of the nodes of the underlying sensor network. A different region pattern couldsignificantly alter the nature and precision of localization. In IGRADELOC, two improvements aresuggested. Firstly, modifications are proposed in the radio range of the fixed-grid nodes, keeping in mindthe actual radio range of commonly available nodes, to allow for routing through them. Routing is notaddressed by GRADELOC, but is of prime importance to the deployment of any adhoc network,especially sensor networks. A theoretical model expressing the radio range in terms of the celldimensions of the grid infrastructure is proposed, to help in carrying out a deployment plan whichachieves the desirable precision of coarse-grained localization. Secondly, in GRADELOC it is observedthat fine-grained localization does not achieve significant performance benefits over coarse-grainedlocalization. In IGRADELOC, this factor is addressed with the introduction of a parameter that could beused to improve and fine-tune the precision of fine-grained localization..