III. d. ii. Make Selections based on queries
          Estimated time:
          5 minutes
Here you will be able to reduce the selection of the graphical elements using a number of boolean operators. Such as, get me all those that are greater than 50... then only those are selected.
In this exercise, you will:
  • Query the GIS borrow site attributes with the "Select by Attribute" feature.
  • Locate the sites with the general soil type(s) that could be used for your project.
  • Use the logic key button to select more than one type of soil in your search.
  •         Start VideoDemo

    Text Version:
    Use the “Select by Attribute” feature to determine which borrow sites have the material type suitable for the project at hand. “Selection” >> Left Click “Select by Attributes” >> In the “Layer:” drop down menu, select the name of the borrow sites layer >> Double Click on “Materials” in the “Fields:” box >> Left Click the “=” button >> Select the desired material for the project based on the material available at each of the borrow sites by double clicking the material in the “Unique Values:” window (Note that a query equation is formed as these selections are made such as: “Material” = ‘Crushed Rock’ (Press “Get Unique Values” to show the options if it’s not already shown)) >> Apply (Note the borrow sites that have the materials selected in the query equation are now highlighted on the map view and in the attribute table) >> Close

    If more than one type of material can be used in the project and is listed in the “Unique Values:” box, use the “OR” logic key between the expressions. An example equation that would select all borrow sites that have Sand or Crushed Rock available is as follows: “Material” = ‘Crushed Rock’ OR “Material” = = ‘Sand, silt, clay mix’