Difference between revisions of "Proxy Yield Map Tutorial"

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(Output layers )
(Sample farm)
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#Login with user: [email protected], password: demo  
 
#Login with user: [email protected], password: demo  
 
#go to 'Farms shared with me'  
 
#go to 'Farms shared with me'  
#Select farm: 
+
#Select farm: 'Demo_ProxyYield'
 
#You should see the main screen of this farm:<br>[[Image:Demo py1.jpg]]<br>
 
#You should see the main screen of this farm:<br>[[Image:Demo py1.jpg]]<br>
  
<br>  
+
<br>
  
 
== Reference layers&nbsp;  ==
 
== Reference layers&nbsp;  ==

Revision as of 12:42, 21 August 2012

Sample farm

For this tutorial we are going to use a sample farm in the Province of Buenos Aires.

The crop is sunflower, and the NDVI reference layer was generated from an image on December 2011, while the harvest was done during the first week of March 2012 (thus, the NDVI was acquired more than 60 days prior to harvest).

The purpose of the exercise is to:

  • simulate that we're on the date that the NDVI image was taken
  • apply 3 different sets of parameters to generate the corresponding proxy yield maps
  • the points yield map is provided as a reference of the actual yields


To Enter the farm:

  1. go to www.geoagro.com, click on 'Farm Services Center' on the upper right.
  2. Login with user: [email protected], password: demo
  3. go to 'Farms shared with me'
  4. Select farm: 'Demo_ProxyYield'
  5. You should see the main screen of this farm:
    Demo py1.jpg


Reference layers 

We are going to use as Reference layers:


To review these layers:

  1. Click on the FSC navigation button.jpg  Navigation button
  2. In the references panel turn on the NDVI20111227 'layer, under the InfoGIS group
  3. In the references panel turn on the RindesP_Girasol_Lote1' 'layer, under the Rendimientos group
    Demo py2.jpg

By turning on/off both layers, we can see the similar growth/yield patterns from the NDVI and Yield Points map


Demo py3.jpg Demo py4.jpg
NDVI - 5mt. resolution - 12/27/2011 Yield Points - 1st week of March/2012



Warning Warning: The Farm Service Center does not show layer's symbology in the current version, this feature will be added soon. To view a layer's symbology, you can download it to a desktop GIS as shown in the Section below


Output layers 

We are going to generate three examples of proxy yield maps based on the NDVI map. We are going to review 3 cases, with:

  • Mean yield of 2.257 tons/ha, and minimum/maximum yields of +/- 20%,
  • Same mean yield, +/-30%,
  • Same mean yield, and minimum, maximum yields corresponding to the min./max. values from the actual yield points map.


In a real case, these values are provided by the farm manager based on past experiences, and current crop conditions. 

The adopted mean/min./max. yields for the three cases are shown in the following table:

Field 1 NDVI Mean Yield +/- 20% [tn/ha] Mean Yield +/- 30% [tn/ha] With min/max
actual yield values [tn/ha]
Min 0.2 1.80 1.575 0.56
Mean 0.537 2.257 2.257 2.257
Max 0.66 2.70 2.925 4.65






To generate the proxy yield maps, we are going to apply a linear interpolation function, matching NDVI values with the linear function, to obtain the proxy yield values. The following figure shows the linear functions, for the 3 cases, for Field 1

Demo py5.jpg


The reference symbology applied is this: Demo py6.jpg


The generated proxy yield maps are shown below

Demo py7.jpg Demo py8.jpg Demo py9.jpg
Mean Yield +/- 20% [tn/ha] Mean Yield +/- 30%  With min/max actual yield values 





Download sample data to a desktop GIS