NEW ORLEANS -- Google, the ubiquitous internet search business, has been asked by a US congressional committee why it was "airbrushing history" by replacing post-Hurricane Katrina satellite imagery on its map portal with images of the region as it existed before the storm destroyed neighbourhoods, uprooted trees and smashed bridges.

"Google's use of old imagery appears to be doing the victims of Hurricane Katrina a great injustice," wrote Brad Miller, who chairs a US House committee, to Google chief executive Eric Schmidt.

The virtual trip through pre-storm New Orleans is a surreal experience of scrolling across a landscape of packed parking lots and marinas full of boats. The reality is very different: entire neighbourhoods are now slab mosaics where houses once stood and shopping malls, churches and marinas are empty of life, or gone entirely.