Views Maps Reader Framework

This chapter explains how to use the Views Maps reader framework to create Views applications displaying cartographic data.

Views Maps allows you to import cartographic data, such as aerial photographs, scanned maps, polygons, lines, and labels, and represent them using a set of IlvGraphic objects inside an IlvManager or any subclass of IlvManager such as an IlvGrapher. The Views graphics framework includes a wealth of predefined graphic objects which you can use to represent map features. This set of graphic objects can be enriched either by coding or by using the Views Studio with the Prototypes package.

Since cartographic data may come from a large variety of data sources with various formats, Views Maps provides a high-level reader framework for easily generating graphic objects to represent the data whatever its original format.

This chapter has two parts:

• The first part describes how to represent cartographic data with Views. It discusses the whole process from loading to graphical rendering. This part covers the following topics:

  • The Classes for Creating Maps: An Overview introduces you to the main classes in the reader framework.

  • Map Features describes map features. Map feature are objects that represent cartographic data as it was read from its source file.

  • Renderers describes renderers and explains how to extend them. Renderers are objects used to transform map features into Views graphic objects.

  • Feature Iterators describes feature iterators and shows how to write a simple reader. Feature iterators are objects used to read cartographic data.

  • Selecting a Target Projection explains how to associate a map projection with a manager.

  • Loading Maps into Views explains how to load an .ilv file and introduces the map loader, a class that you can use to import cartographic data with predefined formats into Views very easily, and how to extend it.

• The second part covers the following topic:

  • The Scale Filters explains how to use scale filters to display or hide information depending on the scale set for the map.