PolarView supports charts in S57/S63 vector format and BSB3 raster format.
Both S57 and S63 chart files have extension .000 for the "primary" cell file, which is what PolarView is looking for. As an aside, there may be additional files with sequential extensions (001, 002 etc), these are updates and PolarView will pick them up automatically.
S57 chart format is open and requires no specific authentication. You can download free S57 charts for US waters from NOAA web site
. Outside US free S57 charts are few and far between.
S63 charts are basically the same vector S57 charts, except they are encrypted and, generally, not available for free. These are often official charts, produced by government
hydrographic agencies around the world. They are also produced privately, i.e. Navionics
ENCs, which are based on Navionics
Chartworld.com is a kind of aggregator and reseller. They sell S63 charts from most official sources as well as Navionics.
To order S63 charts you need to provide something called "User Permit" - essentially a unique identifier of your chart viewer. Charts that you buy will be encoded with this value, and can only be used on a system for which they were encoded. Chartworld.com permits the same set of charts to be used with up to 2 "user permits" per order, i.e. on up to 2 systems.
Prices of S63 charts vary quite a bit, as I mentioned in another post here
If you buy S63 charts, you'll need to go through a process of unpacking and installing them. I wrote a blog post
describing this process - check it out for additional details.