Tool for diff-ing internal guidance decision results

[daniel-j-h]

When we tune guidance knobs in pre-processing (e.g. how far we should look ahead) or when we implement new heuristics (e.g. when we refine the sliproad handler) we should have a tool to analyze the impact on the planet: call it osrm-diff.

The tool should take two paths to separate osrm-extract tmp. files and spits out statistics and coverage reports for changes between two runs:

osrm-diff a/map.osrm b/map.osrm

the diff should include essential features (primarily) for guidance:

• added or removed lanes
• changes in instruction and modifier
• changes in turn angles (larger than a threshold)
• ...

We almost have a tool like that: the debug maps. But the debug map is slow and does not scale for debugging and aggregating pre-processing decisions on a planet scale.

cc @willwhite