For the last eight years, the Federal Emergency Management Agency has been redrawing the nation's stock of flood maps. The previous maps not only left lives and homes in harm's way, but also contributed to the National Flood Insurance Program's descent into a fiscal abyss. But while the new maps are better, they are still imperfect. Greater precision would be prohibitively expensive, said Jeff Featherstone, director of Temple's Center for Sustainable Communities. In a pilot study, Featherstone's group determined that truly detailed mapping would cost about $38 billion — more than seven times FEMA's allotment.