Difference between revisions of "Proxy Yield Map Tutorial"

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To review these layers:  
 
To review these layers:  
  
#Click on the'''//add button '''Navigation button  
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#Click on the '''//add button '''Navigation button  
#In the references panel turn on the '''...... layer'''  
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#In the references panel turn on the '''NDVI20111227'''''' '''layer, under the '''InfoGIS''' group
#In the references panel turn on the '''...... layer''''''<br>'''
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#In the references panel turn on the'''RindesP_Girasol_Lote1'''&nbsp;lay'''''er, under the'''&nbsp;Rendimientos '''group<br><br>
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 +
By turning on/off both layers, we can see the similar growth/yield patterns from the NDVI and Yield Points map
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 +
 
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{| width="200" border="1" cellpadding="1" cellspacing="1"
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|-
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//put table with images + symbology.
 
  
 
//put warning &nbsp;lack of symbology, add symbology in the picture  
 
//put warning &nbsp;lack of symbology, add symbology in the picture  
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| align="center" | '''Field 1'''  
 
| align="center" | '''Field 1'''  
 
| align="center" | '''NDVI'''  
 
| align="center" | '''NDVI'''  
| align="center" | '''Yield +/- 20% [tn/ha]'''
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| align="center" | '''Yield +/- 20% [tn/ha]'''  
| align="center" | '''Yield +/- 30% [tn/ha]'''
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| align="center" | '''Yield +/- 30% [tn/ha]'''  
 
| align="center" | '''Actual Yield [tn/ha]'''
 
| align="center" | '''Actual Yield [tn/ha]'''
 
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<br>  
 
<br>  
  
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
+
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  
  
///put figure
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///put figure  
  
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<br>
  
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the generated maps are shown in the figures below
  
the generated maps are shown in the figures below
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//put figures.  
 
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//put figures.
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<br>
  
 
<br>  
 
<br>  

Revision as of 08:10, 20 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: 
  5. You should see the main screen of this farm:
    //add screen


Reference layers 

We are going to use as Reference layers:


To review these layers:

  1. Click on the //add button 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

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



//put warning  lack of symbology, add symbology in the picture


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 Yield +/- 20% [tn/ha] Yield +/- 30% [tn/ha] Actual Yield [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

///put figure


the generated maps are shown in the figures below

//put figures.



Download sample data to a desktop GIS