Each year, retail analysts and market strategists use sales and economic data to guess what consumers will spend over the holidays. This year, they ll have one more tool: a high-tech apparatus operating 400 miles above America's malls, just outside of the earth's atmosphere.

Satellite images of parking lots suggest the 2010 season will be a jolly one for stores. Car counts from the parking lots of America's prominent malls, like the Mall of Georgia, a 45-minute drive from Atlanta, and the Southtown Shopping Center, 15 minutes from Minnesota, show that average fill rates are up. Parking lots were 32.2% full in 2008 and 31.1% full last year. This year, they've been 35% full, and that's not including Black Friday, as the frantic first shopping day after Thanksgiving is called. Parking lots tend to be much fuller late in the year. For example, last Saturday the Stonestown Galleria Mall in San Francisco was 75% full, satellite images show.

The conventional, terrestrial forecasting clues point to a strong end to the year for retailers, but for confirmation, Thomson Reuters analysts turned for the first time to Chicago-based Remote Sensing Metrics, which uses "satellite imagery, aerial photography, climate data and other publicly available data" to advise corporations and investors.

The images, two of which appear in a Thomson Reuters report released Tuesday, support a prediction based on economic data. The unemployment rate is stubbornly high but stable, while personal incomes and consumption are up.

Thomson forecasts a November jump of 3.5% for its Same-Store Sales Index, versus a 0.5% improvement a year ago and a 7.8% plunge in November 2008. Same-store sales exclude the contribution of newly opened stores and thus show Wall Street which chains are benefitting from increased demand, and not just expansion.

Mall of Georgia, November 28, 2009.

Source: DigitalGlobe, Remote Sensing Metrics analysis.

Parking lot images can't help with forecasting some important measures. Among these are the degree to which stores discount their wares and the amount store-goers spend. Also, 44% of shoppers in a recent survey said they plan to do at least some of their holiday shopping online, according to the National Retail Federation, a trade group. The NRF expects holiday spending to rise 2.3% to $447 billion this season, just $13 billion shy of the record set in 2007. That would mark a sharp acceleration from last year's 0.4% increase and for stores, a welcome rebound from the 3.9% plunge recorded in 2008.

Some analysts say the NRF forecast is too conservative. A Barron's cover story this week quoted research from Wells Capital Management, a San Francisco investment firm, pointing to a 3.5% to 4% holiday sales improvement.

"We'd welcome a higher increase," says a spokeswoman for the NRF. "We'll revisit our forecast in mid-December, but at this point we're sticking with our numbers."

For stock investors, it's not clear whether a strong holiday sales season will send store shares higher, because the stock market has already priced in some of the sector's rising fortunes. The S&P Retail index is up 18% this year, about double the increase for the broad-market 500 index. Even satellite technology doesn t show whether it will press higher.