Landsat Field Yield Prediction Mapping Background
The graphic below shows predicted Landsat yield patterns (which is crop condition at time of imagery) of a field for many season. This historic assessment of the field shows overall stable yield patterns (the darker green areas have higher Landsat values as well as yield, and are in low ground areas). Because the field shows stability, it is a good candidate for management zone applications. The seasons and crops below are, from left to right: 2011 soybeans, 2009 soybeans, 2007 soybeans, and 2006 corn. (There will be seasons without correct clear imagery.)
Continuous or zone maps can be produced and calibrated with yield in different ways from the 30 x 30 meter native pixels: left, continuous Landsat map; Center, zones; Right; zones with smaller areas dissolved.
Landsat can be used to produce field maps that correlate highly to spatial patterns of yield as correlations in the website show. Landsat pixels are 30 x 30 meters; it is typically better to produce a field map with smaller pixel size (as shown above left) but data will always be based on 30 x 30 meter pixels. Maps can be produced as continuous data or in zones (many seasons can be averaged) and can be calibrated with or assigned yield quantities. The examples shown on this page are just some ways Landsat can be applied; other ways shown on the website or custom data or analysis for different crops can be produced. If you would like a product for something other than crops, please contact GIS Ag Maps.
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The progression from raw Landsat imagery to maps to a field extent (below) (or any other extent) is the same for any crop. From left to right the steps are: 1) produce Landsat with pixels that represent correct value to predict yield well enough; 2) use only pixels within the field boundary that do not average in surface outside the field extent or major non-crop surface within the field perimeter; 3) data is interpolated or resampled to a finer resolution for a more coherent map (below, the pixels have be modified from the 30 x 30 meter native resolution to a one-meter resolution); 4) zones can be developed (the appropriate classification method, amount, and minimum size of zone need to be determined). Maps can be calibrated with yield amounts.
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