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[mkgmap-dev] Transliteration

From Steve Ratcliffe steve at parabola.me.uk on Thu Oct 22 12:22:23 BST 2009

Hi Lambertus

> A question popped up on the OSM forum about the many ??? in my maps.
> They are a result of the single code page which is used for the whole
> world and missing automatic transliteration.
> I'm starting to understand what's needed for automatic transliteration:
> detection of source language and various methods for transliteration to
> another language (some languages suffice with 1-on-1 character
> replacement, others need lookup tables etc).
> The subject has been mentioned on this mailinglist before but doesn't
> seem like it's very active, so: is anyone working on this?

There is some transliteration support, but this only kicks in if the
target character set is ascii.

I know I said a few months back that we should also do the same thing
when --latin1 is supplied, and I suppose now is the time!

We can also improve the range of translitterations using the perl
script that Ævar Arnfjörð Bjarmason recently posted.  This lead me to
find a number of resources that might be useful, including
http://site.icu-project.org/ which claims to be comprehensive but may
or may not be useful for our purposes, I've not investegated it.

> The discussion on the OSM forum starts here (and further down):
> http://forum.openstreetmap.org/viewtopic.php?pid=42175#p42175

The thing I would like to add is that code-page is not particularly
useful for a general purpose map such as the one you produce.  See for
example, http://wiki.openstreetmap.org/index.php/Mkgmap/i18n where you
can see a screen shot with Russian characters.  Looks great, but you
need firmware that supports that character set and even units that you
buy in the country in question may not.

There is also a unicode/mbcs format, which I have never seen and is
as far as I know again dependant on having firmware support and so
would be of no use to you either, even if implemented.

As you say, until we can split tiles along country borders
varying parameters between different tiles is not going to be
satisfactory, even if there was an automated way of determining what
they should be.
(As an aside I looked into what is needed to do that and I think I
understand it now.)


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