Access Cookbook

Create a Geographical Map Interface

Problem

You want to display a map and allow users to click on regions of the map. You want the form to react based on which region is clicked on. The regions aren’t necessarily rectangular. How can you do this?

Solution

You can accomplish this task using a combination of bitmaps and transparent command buttons. Depending on how far from rectangular your shapes are, this task may be trivial or quite involved. By making the command buttons transparent, you make the application appear to react directly to mouse clicks on the map.

Open frmWesternUS in 09-03.MDB (Figure 9-7). This form has been created with an imported bitmap file as the background. Above each state’s image on the map there’s at least one command button with its Transparent property set to Yes. Figure 9-8 shows the form named frmWesternUSDesign, in which the buttons are not transparent. Here you can see the actual layout of the command buttons.

Figure 9-7. The finished map form, frmWesternUS, with transparent buttons

Figure 9-8. The same bitmap form with buttons showing

To implement similar functionality in your own forms, follow these steps:

1. Create a new form. Click anywhere in the detail section of the form, and select Insert → Object (or use the form design toolbox to place an unbound ...