Making Maps Navigable - Programming GPS and OpenStreetMap Applications with Java - page 104

Therefore, map compilers for navigation systems can be divided into
three independent processes after cleaning and clipping a source map:
1. The cartographic branch creates a purely visual map|a number of
image tiles; or tile information for on-board rendering. The visual
map uses the full geometry with all available shape points.
2. The second branch creates a navigable network. The map data is
reduced to maneuver points to build a graph. The network is validated
to be closed to ensure that any node (origin) can be routed to any
destination node.
3. The third branch compiles the administrative part of the map. Ad-
ministration has to be organized in hierarchical structures for the user
to search his destination with various approaches. Redundant char-
acter strings are removed to save space and addresses are connected
to geographic positions.
It is vital that all three branches are compiled from one map source to
avoid the end-user loosing his confidence in the system, when the moving
vehicle is depicted driving across a eld|or lake.
8.2.1 Slicing Germany
We can now reuse the data from the OSM compiler. The next project GER
should minimize the entire map of Germany into small pieces for effective
processing on personal computers or smartphones.
The project will be unfolded in
../OSM.compiler/products/GER
+-- admin
+-- carto
+-- networks
The cleaned osm file of Germany produced on page 96 represents the start-
ing point of the project-specific compilation. The file should reside in the
../OSM.compiler/deliveries/germany.clean.osm
Processing a 10 GB file with osmosis and OSMparser takes hours and
would take days to pass different branches to a final PSF. Today, many
personal navigation devices (PND) can be updated via the internet and
the end user probably doesn't want to download 10 GB. Some Europe
PSFs are about 100 MB and can be loaded in one or two hours.
The next step is a product-specific data analysis. The batch file
country.bat 1 was created to split the entire Germany map into different
1 The name indicates that it can be copied, modified, and applied to any country.