With Satellite Images, Wall Street Analysts Spy On Wal-Mart : Planet Money Crowded parking lots suggest higher sales.

With Satellite Images, Wall Street Analysts Spy On Wal-Mart

satellite image of Wal-Mart parking lot
Remote Sensing Metrics/via CNBC

This is a Wal-Mart parking lot in Wichita, Kansas, as seen from space.

It may not look like much to you. But analysts at UBS recently started using pictures like this of Wal-Marts around the country to help them estimate the company's sales. (Crowded parking lots suggest higher sales.)

As it turns out, lots of people are using images from surveillance satellites as a way to gauge economic conditions. CNBC had a two-part series on the issue this week, plus the requisite slide show of satellite images.

Some analysts look at satellite pictures of big ports, as a proxy for broad economic activity. Others look at crops.

Here's a fun, geeky explanation from CNBC of how a firm called Lanworth uses satellite images to predict the prices of corn and wheat:

Using infrared and microwave images of the entire planet taken twice a day, Lanworth can distinguish between each type of agricultural commodities — corn, soybeans, wheat and on and on—and discover the total number of acres of each planted overall. Infrared images capture the chlorophyll in the plants, and microwave images pick up the degree of moisture in the crops.

By monitoring the health of those acres over time, Lanworth’s analysts can spot any changes that can affect supply and demand in the commodities markets: diseases, floods, fires and other agricultural calamities.