Changing Map Layers
When you initially view a map you are looking at it from a very high level. If you use the Zoom In option to make the map larger, you are effectively getting closer to the map. As you get closer and closer you will keep seeing more information on the map. It’s as if you are jumping out of a plane with a parachute and as you get closer to the ground you keep seeing more details. Crystal Reports shows you this detail information using layers. As you zoom in on the map, new layers get displayed.
Crystal Reports lets you choose which layers to show on a map as well as the order that they are shown in. The Layer Control dialog box gives you an interface for seeing which layers are available for each map and setting their properties. It is shown in Figure 14-17.
Figure 14-17. The Layer Control dialog box lets you modify visible layers.
To open the Layer Control dialog box, right-click on the map object in preview mode and select Layers. To change the order in which the layers appear, click on the layer you want to change and click the Up or Down buttons.
You can also add additional layers or remove existing ones. To add new layers, click the Add button and navigate to the installation folder:
In this folder are all the available map layers. Select the one you want and click the OK button to add it to the list. If you don’t want a particular layer anymore, select it and click the Remove button. You can also hide the layer, but not completely remove it, by un-checking the Visible property.
As the user zooms in on the map, the point at which a new layer becomes visible is controlled by its zoom range. You can set the zoom range by clicking on the layer you want to modify and then clicking on the Display button. This opens the Display Properties dialog box shown in Figure 14-18.
Figure 14-18. Setting the display properties of a layer.
The two numerical values set the min and max zoom ranges in which the layer appears. If you uncheck the option Display Within Zoom Range, then the layer will be visible at all times.
