Creating management zones and writing prescriptions (BETA)

Imagery brought into your fields through FarmQA's integration with Planet can be used to help you write variable rate prescriptions for your fields. Any NDVI Planet image can be used to create custom management zones for your fields. Management zones can then be used to write any variable rate prescription you'd like for your fields, and ultimatley exported to use as you see fit. Check out the article below to learn how to create management zones and write variable rate prescriptions for your fields in FarmQA. 

Understanding the interpolation methods used to create your management zones

Create a management zone from Planet NDVI imagery

Writing and exporting a prescription from a management zone

Understanding the interpolation methods used to create your management zones

FarmQA has three built-in interpolation methods that can be used to create management zones from your imagery or soil samples: the Equal Interval method, the Quantiles method, and the Natural Breaks method. These likely aren't familiar terms, and it's important to understand the differences between these methods while you're setting up your zones. To give you a better idea of what your zone maps will look like when using one of these methods, we have created management zones based off of the Planet NDVI image below. Each zone map will have 4 zones with a minimum zone size of 0.5 acres. 

Each image below shows you what creating management zones based off of image above will look like if you're using the Equal Interval, Quantile, or Natural Breaks method of interpolation. We provide a definition for each method to give you a better understanding of the process we use to generate your zones. Under each image you'll find a table that breaks down the range of NDVI values in each zone as well as the total acreage each zone takes up. 

Equal Interval

Creates zones that equally divide the range of all values and then places data points into zones according to their value.

Zone maps produced by the Equal Interval interpolation method might be considered conservative by some. Most low-health zones around the edges of the field are captured by Zone 2 with Zone 1 representing few more dramatic low-health zones. The field is largely homogeneous with Zone 3 taking up by far the most space. If you're not as concerned about smaller high- or low-yielding spots in your fields, using the Equal Interval method to produce your zone maps might work best for you. 

Quantiles

Orders the data by value and then places them into zones such that each bin has the same number of items.

Due to each zone being approximately the same size, the zones that represent high and low values (Zones 1 and 4) are much larger than the dark red and green regions in the original image. This interpolation method has also greatly reduced the range in values for Zones 2, 3, and 4, with each having an NDVI range of 0.02 while Zone 1 has a range of 0.23. We would generally not recommend using this method for producing zone maps from NDVI imagery unless if you're using a base image that has high- and low-health areas that take up roughly the same area within a field. 

Natural Breaks

Groups data points into zones such that the difference between the values across zones is maximized while the difference between values within zones is minimized.

The zones generated by the Natural Breaks method most closely represent the breaks seen in the original NDVI image. The high- and low-health zones represented by the dark green and dark red values in the original image are well covered by Zones 1 and 4. Note also that high-health patches are better captured in Zone 4 in the image below compared to other zone maps. 

Create a management zone from Planet NDVI imagery

• Log in to your FarmQA account from the web app if you aren't already. 
• Within the Map tab, locate the field you want to create management zones for and click on it. 
  
• In the slide out map pane, click the Edit layer icon next the map layer that contains the image you want to create a prescription zone from. 
• Locate the image you want to use, then click the Create management zone icon (pictured below). 

• Fill out the following information to setup some parameters for your management zone (pictured below): 
  1. Give your management zone a Name.
  2. Add a Description to your management zone if you want to. 
  3. Toggle on the Show labels  option.
  4. Use the Clustering Algorithm dropdown menu to choose a method used to generate your management zone map. For most users, we recommend the Equal Interval method. 
  5. If desired, set a Minimum polygon size (ac) for your management zones. This will depend on what you want to get out of your management zones as well as the size of your field. 
  6. Set the Number of zones you'd like for your field. 
  7. Use the Colors dropdown menu to choose a color scheme to color your management zones with. If desired, you can toggle on the Invert option to swap the colors used to color your zones. 

• Click the Preview button to check your work before downloading your management zone. From the Preview page, consider doing the following (pictured below):
  1. Change the Minimum polygon size (ac).
  2. Use different Colors to color your management zones.
  3. Either Add or edit the ranges of the cluster groups that will be used in your management zones. 

• When you're satisfied with your management zone, click the Submit button at the bottom of the screen. You'll now be able to access your management zone from the slide out map pane in the Map tab. 

Writing and exporting a prescription from a management zone

• Log in to your FarmQA account from the web app if you aren't already. 
• Within the Map tab, locate the field you want to create a prescription for and click on it. 
• Click on the Zones button in the slide out map pane (pictured below). 

• Find the management zone you want to write a prescription for, then click on the Create prescription  icon (pictured below). 

• In the Specify attributes window, input the name of the attribute you're going to be writing prescriptions for, like nitrogen or seeding rate. Use the dropdown menu to the right of that text box to specify whether it's going to be a Number or Text based prescription. 
• Click the Add button below the attribute name to add another attribute to create a prescription for if want to. 
• Click the Next button to continue writing your prescription (pictured below). 

• In the Specify the values for each zone window, put in the prescription values you'd like to associate with each of your management zones. 
• Fill in more information about your prescriptions in the Description box if you'd like to provide more context to your prescription. 
• When you're done, click the Download button (pictured below). 

• Your prescription will be downloaded as a zipped shapefile. The zipped folder will contain four files: .DBF, .PRJ., .SHP, and .SHX. 

Please contact FarmQA Support with any further questions