I live in northern RI. My favorite lakes already have HD maps through the major mapping systems. I find most of them to be pretty similar and noticed if 1 has it wrong, they all have it wrong. For the local ponds that I fish that dont have HD maps they are usually shallower and overgrown with vegetation so for the most part you are fishing visual targets anyway. I LOVE the navionics app on my phone. I do a vast majority of my research on my phone or tablet and it has translated to some quality off-shore fish in lakes I was unfamiliar with and wouldnt have caught without it.