In Las Vegas, another city crushed by the burst of the housing bubble, the market hit its bottom in March. But while there has been an increase in sales and construction activity since, home values have been slower to rise.

And in Atlanta, another city hit hard by the economic downturn, the situation is worse today than it was a year ago because of a stubbornly high number of foreclosures.

When all is taken into account, the picture evokes caution: the overall value of homes in 20 metropolitan regions tracked by Standard & Poor’s Case-Shiller index remained unchanged, and prices are still sitting at their lowest point.

“Because of new buyers having difficulty getting mortgages and because of the still-large number of foreclosures hitting the market in some parts of the country, it’s hard to say that we’ve turned a corner,” David Blitzer, chairman of the index committee at Standard & Poor’s, said in an interview.