[mkgmap-dev] Overview map

Sun Mar 12 18:34:34 GMT 2017

Gerd's comment about looking at the overview map, prompted me to look at
mine, and I realised I didn't have one (or it is empty), despite me having
--tdbfile specified - the help for this option says an overview map will be
created. I assume I am not getting an overview map because I don't have
--overview-levels specified. Would it be better if the default for
--overview-levels is not an empty string when --tdbfile is specified?

The documentation for --overview-levels is not very clear. From inspecting
the code it looks like the format expected is similar to the format expected
by --levels and that the overview level numbers should be greater than the
normal levels. Can the documentation for this be improved? Also, what is the
benefit of specifying something like --overview-levels=5:15,6:13,7:11 over
the much simpler --overview-levels=15,13,11 and have mkgmap work out the
next free levels. Could we simplify this?

Regards,
Mike