Map Tile Layers How Map Content Is Organized

8-6 Oracle Fusion Middleware Users Guide for Oracle MapViewer

8.1.3 How Map Content Is Organized

This section describes how the JavaScript client internally organizes various map contents when displayed a map inside a Web browser. An application typically places one master HTML DIV object on a Web page, and the JavaScript client adds various content layers inside this DIV object. The map content displayed by the map client is organized by layers. When the application script invokes appropriate map client API, map layers are created inside a map container. The map container is a user-defined HTML DIV object. You can customize the size and the positioning of the map container inside the Web page. Figure 8–3 shows the layout of the map layers. Figure 8–3 Layers in a Map As shown in Figure 8–3 , there are five different types of map content layers: map tiles, theme-based FOI, user-defined FOI or redline, information window, and fixed figures. All layers except the fixed figures layer are moved as a whole when the user drags the map. These movable layers are automatically updated by the map client when the map is dragged or zoomed. The fixed figures layer is never moved..

8.1.3.1 Map Tile Layers

A typical Oracle Maps application has at least one map tile layer, which assembles and displays pregenerated map image tiles from the map tile server. The map tile layer displays static map content that does not change very often, and it is typically used as the background map by the client application. For example, in the sample application described in Section 8.1.2 and illustrated in Figure 8–2 , the ocean, county boundaries, cities, and highways are all displayed as a map tile layer. Only limited user interaction, such as map dragging, can be performed with a map tile layer. Map Tile Layers Theme-Based FOI Layers User-Defined FOI and Redline Layers Information Window Layer Fixed Figures Layer Map Container HTML DIV Object Oracle Maps 8-7 A map tile layer is usually associated with a MapViewer base map, and is managed by the MapViewer server. However, you can configure a map tile layer to cache map image tiles served by an external non-MapViewer map provider. The Oracle Maps client can also display a custom or built-in external tile layer served directly by an external tile server. The built-in Google Maps and Microsoft Bing Maps tile layers are examples. For more information, see Section 8.6, Built-in Map Tile Layers Google Maps and Bing Maps and the JavaScript API documentation for class MVGoogleTileLayer and MVBingTileLayer. If you need to overlay your own spatial data on top of the Google Maps or Bing Maps tile layer, see also Section 8.7, Transforming Data to a Spherical Mercator Coordinate System . Map tile layers are always placed at the bottom of the layer hierarchy. These layers display static and background map contents. When multiple such layers are included, they must all have the same coordinate system and zoom level definitions. Internally, the map tile layers are usually larger than the size of the map DIV container window. This allows additional tiles to be fetched and cached by the browser. As a result, these tiles will be immediately visible when the map layers are dragged around by the user.

8.1.3.2 Theme-Based FOI Layers