Section 6

Section 8 

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 Tradeoff Analysis: On-line course Kenya

Section 7 - Visualization of results

 

After running the simulation model, we are now getting to the point where we would like to view the results. The large number of simulations results in a large number of records in the output files representing different fields, tradeoff points, crop cycles and repetitions. In many cases it is therefore useful to aggregate the results before graphing them. Finally we can go to the grapher of the Tradeoff Analysis System to show the graphs.

 

Merging and Aggregation

At this step the user can aggregate (or average) simulation output according to criteria the user selects. 

The Machakos simulation model operates at both the field-level (or parcel-level) and farm-level, and produces two corresponding output files. Prior to aggregation the user can use the Merge button to read the parcel-level data, create area-weighted farm-level variables, and merge them with other farm-level variables.  

Aggregation is done using a SAS batch file that carries out the aggregation. The user must select the input file of data to be aggregated, the output file where the results will be written, and the variables defining the aggregation (e.g., tradeoff variables, other i.d. variables such as village or region). The aggregation procedure averages all the variables according to the aggregation variables that are selected. To calculate, for example, the average values for each of the tradeoff points, we select the tradeoff variable TNO as the aggregation variable. 

 

Exercise 13: Aggregation

  1. If we aggregate results over the tradeoff points, how many records should be in the output file?
  2. Carry out the aggregation and check the number of files in the output file.

 

Graphing Results

An important form of viewing your results is to display them as graphs. To view your results as graphs, one has to select one or several data files. One can add names to the different file names and enter a title for the graph. If all the data are set, the graph is viewed by pressing the graph button. The grapher is based on the commercial TEEchart software.

 

Exercise 14: Graphing Tradeoffs

  1. Go to the graph-button in the tradeoff analysis system and select the output file from a simulation (a file that has not been aggregated). Graph two of the variables.
  2. Now graph the aggregated file for the same two variables. What are the differences?

 

Section 6

Section 8