Related question: Where can I find GA VFR maps for Australia?
For various areas of the world, where are authoritative General Aviation VFR maps, charts, and so on available on the web?
The short answer is the most of the world is not covered very well, not even on paper charts. Operational Navigation Charts (ONC) are available for most of the world, but they're not approved for navigation. That said, if there's nothing else available, an ONC chart plus GPS can still be useful.