In this lesson we'll go over how to select and generate Iso-Chemical Contour maps.
In the menu section on the left side of the screen, you’ll see numerous options…. click on the “report tab”. Then select the “Iso-Chemical Contours” selection.
Starting at the top of the menu, in the field titled “Site Map” you’ll be able to select which map or image you want to generate an iso-chemical contour map on (see the “How To Add Sample Location Maps'' or images” video for more detail). Select the image you want to do an iso-chemical contour on and then select the dates you wish to contour. The software will not let you pick dates for which there are two data points on the same well/location. If this happens, a black box with a list of overlapping sample dates will appear. If you want to select another date, you will have to unselect the date first, and then select the new date.
On the image to the right you will see individual black boxes with a “check mark” and a numeric value in it. This value is the total of all the chemicals selected in the “select substances” field. You can do any combination of chemicals you would like or even just individual chemicals. If you want to do a contour without including that location, just uncheck the checkbox and it will be excluded from the contouring. If the well was non-detect for the chemicals selected, no black box will appear.
To create more realistic contours we allow the user to place a theoretical “zero” value boundary around the area of contamination. This requires interpretation by the user and is not required, but doing so makes the contours more realistic. To place the “zero” values, simply move your cursor to a location you would like a zero value placed and right click the mouse. If you change your mind, simply uncheck the check mark and it removes the zero value.
Moving down the menu, you will see a field for turning a “zero line” on or off, a field for adjusting the number of contours you would like to see displayed, and there is also a field for turning the contours into a heat map. In addition there is a field for contouring in either a logarithmic scale, or a linear scale. Simply select your preferences for each and then generate your report.
You can also see the field for re-titling the map to whatever title you would like and you can change the units that the contour is displayed in as well. It will default to the PPB setting.
At any point you can hit the “Generate Report” button and it will generate a PDF of your image. Use the image or images in your report that you feel are best. Again, hit the orange save button to save your settings.
And that is how you select and generate Iso-Chemical Contour maps!