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Tuesday, March 20, 2007 10:44 PM CDT
Mapping systems offer new way to look at land you farm
By DENNIS BOWMAN, Crop Systems Educator
UI Extension Office
I love maps. If you are going to tell me how to get some place, don’t give me directions — show or draw me a map.
Good maps can quickly communicate the big picture, giving the viewer an understanding of how places relate to each other. One of the side benefits of Precision Agriculture has been the amazing ease at which really good farm level maps can now be produced.
In the early days of Precision Agriculture, about 10 years ago, early adopters that had purchased a GPS unit and some expensive software often helped cover the cost by selling their services to create precision ag maps for others. One of the most popular software packages especially among dealers and consultants sells for $5000. You can see why they were anxious to spread those costs over more acres.
This type of software is commonly referred to as GIS, Geographic Information Systems. This type of software can take a stack of datapoints that have location information such as latitude and longitude and place them on a map. Several set of data can be displayed on the map at the same time. The power of GIS software is that it allows you to manipulate and analyze the data.
If you would like to make some maps but don’t want to invest hundred or even thousands of dollars in GIS software there are now some nice options available.
One of the simplest ways is to go online. The University of Illinois, with support from IEPA and IDNR, has created a wonderful Web site called the Resource Management Mapping Service (http://www.rmms.uiuc.edu/website/rmms/). You can go to this site, and then click on “Help” to view the getting started instructions. Soon you will be zooming in on the areas you’re interested in and turning the numerous data layers on and off at the click of your mouse. This site takes away a lot of the GIS headaches. This site’s developers have accumulated many good data layers and made sure they are all using the same reference system, so that everything lines up correctly. The only drawback for me is that it is online and for those of us still on dial-up internet connections it takes a fair amount a patience waiting for the information to re-download and redraw each time you make a change. However on a fast connection it is amazing.
As the limited amount of free hard drive space on my computer will prove, I like to accumulate GIS data. I personally like having it right here, where I can access it quickly. However, it can be challenging to find good data sets with the correct geo-reference system. There is now a great place to go to start building your GIS data library. The NRCS Data Gateway is a one stop online shopping center for agricultural GIS data. The latest geo-referenced aerial photos, digital soil surveys, and topographic sheets are some of the layers that are available to order. You can even get a sanitized version of the FSA Common Land Unit, CLU layer. All the owner and history data has been removed but you do have the boundary lines and the calculated acreage. When you get ready to checkout with your selected data make sure you request it in “NAD 83 UTM 16N” projection and as “shapefiles”. I don’t have room to explain projections today but take my word for it.
If you have access to a fast internet connection the data is free to download. You give them your email address and they will send you an email when your data package is ready to download; the wait varies from a few minutes to several hours. For a small fee they will mail you a CD or DVD with your requested data.
After you get your data how do you look at it? I recently spent some time checking out free GIS software. There are now several available. The one I liked the best was TatukGIS Viewer. It handled a variety of data formats. It also had some good options for displaying layers such as being able to make some layers transparent, very useful when you start stacking layers. The tutorial and help files enabled me to learn the basics quickly.
Dennis Bowman is an Extension educator, crop systems, for University of Illinois Extension.
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Jerry Jackson wrote on Apr 26, 2007 7:54 AM: