Public Release: 

Purdue Gives Farmers 20-20 Vision From 30,000 Feet

Purdue University

WEST LAFAYETTE, Ind. -- By the year 2020, farmers will check their crops by checking satellite images on the World Wide Web, says Chris Johannsen, a remote-sensing researcher at Purdue University. He has pulled together information to help decode aerial and satellite images and has published it on the first-ever Agricultural Validation and Verification Web Site.

"When a farmer sees a problem on a satellite image, he'll pull a GPS (global positioning system) unit out of his pocket, use it to guide himself to within a meter of the exact location, and treat it," Johannsen says. As a result, the farmer will nip nutrient deficiencies in the bud, stop pests before they spread, prevent crop damage and use less pesticide.

Jon Arvik, technology consultant with Foundation Consulting Services in Erie, Colo., agrees, "Using satellite images will be relatively routine in the next century, like watching the weather is today. By then we'll be farming by the foot rather than by the field."

However, farmers need three things to make this system work. First, they must be able to get satellite pictures of their fields. Second, they must understand what the images can tell them. And third, they must be able to afford the technology.

The images are coming. By the year 2008, more than 50 commercial remote-sensing satellites will be circling the globe, Johannsen says. The thousands of digital images they'll send back will show farm fields made up of different-colored, information-packed pixels. They'll be able to show changes in areas as small as a meter.

But the images will come without a color-coded key. Farmers will need to know that a certain gray indicates hail damage or that a particular yellow-green signals the beginning of an insect infestation. Private companies will collect some of their own ground-truth data to decode their images, Johannsen says, but both farmers and company researchers need a nationwide, unbiased source of image-decoding data.

That's where Johannsen and his crew have stepped in. Johannsen's graduate student Esther Owubah created the Agricultural Validation and Verification Site ( She collected soil, crop and management data from research fields at the Purdue Agronomy Research Center and put the data on the Web. Then she organized the information through a geographic information system (GIS), which allows users to look at different types of information as overlapping layers of a map.

Eventually, the site will include information on disease and insect problems at the research center. Remote-sensing specialist Paul Carter, another member of Johannsen's team, has been monitoring problems in the fields at the research center and at Davis-Purdue Agricultural Center, a research farm in eastern Indiana. He checks fields for hail damage, weed infestations, waterlogged spots and other anomalies, then correlates those findings with changes in the satellite images.

Currently, private or public researchers with satellite images of the Agronomy Research Center can compare their images to the data Owubah has compiled. The Web data can help them develop a sort of map legend or key for their satellite images of Midwestern farm fields, Johannsen says.

"It's hard to find a site like this where you have multiple crop types and tillage systems in one spot," says Marshall Beatty, chief agronomist for Litton/Emerge, a company developing Internet-based, precision-farming software for farmers. "The site is a wonderful tool. It also can address a huge educational gap for growers and help them interpret remote-sensing imagery."

Johannsen sees himself as starting a trend that puts university research data where farmers and agribusinesses can use it for precision agriculture. He envisions a time when each state maintains a Web site that has the key to decode satellite image data for that state's major crops and soil types. With a wide array of universities to choose from, corporations, farmers and researchers will be able to find information that closely matches their own crops, climate and soil, Johannsen says.

"Five years from now nearly every state will have a similar agricultural validation Web site," Johannsen says. "We hope they'll use ours as a prototype."

The prototype Web site will be useful only if precision agriculture makes money for farmers. While no one yet knows if or where the technology will pay, many agricultural businesses are betting on it. A 1997 national survey by Purdue agricultural economist Jay Akridge found that 30 percent of agricultural services dealers expected to be in the business of interpreting GPS farm data this year. The percentage of dealers betting on GPS was substantially higher in the Corn Belt.

Johannsen also bets it will pay. He and John Trott, director of Purdue Agricultural Centers, already plan to expand the Web site by adding information from the Davis-Purdue Agricultural Center. The new data will include GPS yield information from the last two years, as well as remotely sensed images of crops and forests.

As the project evolves, Trott plans to involve Purdue Cooperative Extension educators in county offices. "We're getting key Extension educators involved in the research going on," Trott says. "They need to understand the technology so they can help their producers overcome hurdles on the farm."

Johannsen's Web site is part of a larger project funded by NASA's John C. Stennis Space Center to help companies use remote-sensing technologies in environmental consulting, land use planning and natural resource management.


Chris Johannsen, 765-494-6248; fax, 765-496-2926;
Paul Carter, 765-494-6247; fax:, 765-496-2926;
Esther Owubah, 765-494-0796;
Jay Akridge, 765-494-4327
Jon Arvik, 303-828-9535; fax, 303-828-5170;
Marshall Beatty, 765-426-1259;

A color photo of Chris Johannsen collecting global positioning system information in a farm field is available. The photo is called Johannsen.vandvsite.

Purdue agronomist Chris Johannsen uses a global positioning system backpack unit to find the right spot in a farm field to take a soil sample. He has established a Web site to share data that helps decode information from aerial and satellite images of crop fields. (Agricultural Communication Service Photo by Tom Campbell)
Color photo, electronic transmission, and Web and ftp download available. Photo ID: Johannsen.vandvsite

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