Data Collection and Information

The data on the insects in this project was collected in two ways.  The first was using traps to catch the insects.  Yellow sticky traps were set up at a series of greenhouse operations throughout the valley.  These traps were checked periodically throughout the summer of the project and the presence or absence of each insect species was recorded.  The other method used was the sweep method.  The basic concept of the sweeping method of collection is to take a net and brush it through foliage to catch any insects hiding in the foliage.  Based on the results, the sweeping method seems to be more appropriate for catch Lygus since the numbers of insects found was much greater that the results from the trap method.  

The original data used in this project was not in a geographical database.  Instead all the data, including the UTM coordinates was stored in a pair of Microsoft Excel files, one for the trap data and one for the sweep data. The coordinates were stored in a single column, in the form  UT10526536 5432995.  This coordinate states that we are using the UTM 10N coordinate system, with x and y coordinates equal to 526536 and 5432995 respectively.  The entire database had to be reprocessed to two columns of X and Y coordinates for the next stage of the project.  In addition, there was a great deal of data that was of no use to the project, including the current status of the insect samples.  The databases were simplified down to only information about whether or not each species of Lygus was found in a specific area.  

Next, 6 separate tables were created in the same .dbf format as used by Arcview.  There is a trap table and a sweep table for each of Lygus Shulli, Lygus Hesperus and Lygus Elisus.  Each table only contains the coordinates of samples where that insect was found.  Sample sites with a false result were not kept for this experiment. Finally, the resultant tables were each taken through a series of data conversions, finally resulting in a set of 6 Idrisi raster files with a non zero value in a raster cell representing the sample sites.  The conversion process is detailed in the diagram below.  Once the conversion steps are complete it is time to run the actual data analysis.

Figure: Cartographic Model Part I - Pre Analysis Data Preparation.



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