Render process

The following chapters give an overview starting from data loading via the Database to the rendered map using the MapPainter.

This initial description will be incomplete, descriptions and chapters will be added on demand.

Index and data files

On the lowest level the databse consists of a number of data and index files, in some cases a file contains both an index and the actual data. For a detailed description of the individual files see Database files.

For each file an corresponding C++ class exists that wraps access to these files.

For rendering mainly the files that contain information regarding nodes, ways, areas and water/sea/coastline are relevant. In the following these are summerized as “map data”.

The Database

The Database class wraps most of the above files, controlling initialisation, deinitialsation and access to these files. Databse is mainly a convinience wrapper to the low level data and index classes.

Characteristics of map data as retrieved the Database

The database allows you to retrieve map data for each object type (node, way, area) individually and let you control which data types are retrieved.

Database allows you to retrieve data in a given rectangular area (as seen from the coordinates. On ground and depending of the used projection the area is not rectangular at all).

For the returned data the following statements are valid:

The MapService

To be written…

The MapPainter

To be written…