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DIY zone maps

By John Dietz

Growers and ranchers who
want to do their own zone maps now have the option of using a pair of public
access websites to augment their precision farming technology.

Available through, the sites are part of the Upper Midwest Aerospace Consortium
(UMAC), which has an office at the University of North Dakota in Grand Forks.
The office functions as a public access resource center for integrated earth
sciences, including agriculture, forestry, and education.

UMAC launched Digital
Northern Great Plains ( in 2003 as an online system for public
access to a collection of several thousand satellite images and related
geospatial images. 

DNGP is constantly updated
with new satellite images of the northern Great Plains and some aerial photo
images as frequently as weekly during the growing season. Most have been
acquired in the past 10 years, but the oldest images date back to 1972.

The images are supported by
a matrix of conventional maps for soils, topography, crop production, and population.

In 2008, UMAC released
ZoneMap ( to extend its outreach. ZoneMap is interactive and
utilizes the DNGP platform. Tutorials and hands-on training classes are

ZoneMap overcame one limit
of DNGP, says John Nowatzki, ag machine systems specialist and instructor,
North Dakota State University in Fargo. Before this he could only download
images from DNGP to study the history of a field.

With its interactive
function, ZoneMap can produce usable field maps broken into management zones
for purposes such as variable-rate application, drainage work, and weed
control. It will accept GIS-based data uploads for yields, electrical
conductivity, and soil nutrient analysis. Confidential information is password

“ZoneMap does the analysis
for you, without having to do anything else, from the home computer,” he says.

Using ZoneMap one field at a
time, growers and ranchers can locate fields, compile layers of images, upload
their own field data, and watch the system generate accurate maps of management
zones for a field. They can even download the maps to the farm computer as
shapefiles at no cost.

A zone is an area in a field
where treatment can be uniform. The field will display as several contiguous
polygon shapes on the farm computer. Internally, the software is working with
points in the DNGP shapefiles.

To be useful in the field,
point shapefiles must be converted into the polygon shapefiles that are
specific to each farm’s variable-rate controller.

The file format is ZoneMap’s
remaining technical issue.

“I’d like to see the
programming become more useful,” Nowatzki says. “A prescription zone map should
be in the form of a polygon shapefile. If you download a map in point format,
you first have to convert it to a polygon shapefile, and that’s just too

Software is available for
converting a point shapefile to a polygon shapefile, but not on ZoneMap in

Still, the digital data
mountain at Grand Forks is interactive and quick. Once registered, users can
select fields individually, compile data including recent updates, and download
it to the home PC.

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John Nowatzki


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