1. Bring up the Workshop layout model again.
   • From the Point Data Plot display control window click on the edit image: .
   • Bring up the Properties dialog for the symbol by right clicking on it and selecting the Properties... menu item.
   • Note that the name of the parameter we are using is "IDN".
   • Press the Cancel button to close the dialog.
2. Now, back to the Point Data Plot control window let's see what parameters are available in the data set.
• Normally we would do the following but the current version of the IDV does not support it. Select the Help->Details... menu item to bring up the Display Control Details window. This lists the fields available in the data set.
• So instead, we will look at Details tab in the Properties Dialog for the Point Data Source.
• Note there is no IDN field. However, there is an ID field in the data.
• Close the Properties window.
3. Once again, back to the Layout Model Editor.
• Bring up the Properties dialog for the symbol.
• Click on the button to bring up the list of all parameter names. Look for and select the "ID" parameter under the point data.

  A note on the data source name

• Aha! We were using the IDN when we should have been using the ID, the IACO Station ID.
• Select that parameter. Notice that the parameters can be a comma separated list. Click the OK button and save the layout model (select File->Save).
• You should now see the station identifiers in the display.
4. Now, how do we handle the case where we have lots of layout models for data that has "ID" like fields and then we encounter data with some other field name, e.g., "the_station_id"? Do we go and change each and every model?
5. Now, let's spend some time in building some other layout models.
   • Start fresh.
   • Go to the CONUS projection with the Projections->Set->US->CONUS menu item.
   • Load in US city locations with the Displays->Locations->US->U.S. Cities menu item.
   • Select the Layout Model button.
   • Edit the Location layout model.
   • Try adding a Shape shape.
   • Select some shape and press Apply
   • The location has a pop attribute. Try scaling the shape this value.
     • Go to the Scale Size By tab in the Properties Dialog
     • Enter pop for the parameter.
     • In Data Range enter 1000000 in the second field.
     • Enter some scale range. e.g., 0.5-5.0
     • Press Apply
   • Try doing a color by pop

Unidata IDV Workshop for version 2.7u2 > Accessing and Displaying Data > Point Observations