[mkgmap-dev] address search and the --lower-case option

Wed Apr 26 15:09:31 BST 2017

Hmm,

the longer I try to understand the more confused I am :(

I've learned now that a line like
expand ß to  s s
in sort/cp1252.txt
really seems to tell the Garmin software that the ß is a replacement for ss.
When I change it to
ß m m
and compile a map Mapsource finds shows Immelmannstraße when I type Iß , so I think this is ensured.
Still, the search is done wtih some kind of "ignore case" algorithm which probably also uses the content
The SRT file (which is compiled using the content of cp152.txt) contains further information which says how to sort this "expanded" character, so it is not
completely equivalent (Strasse comes before Straße)
What I don't understand is this:
How can it work in combination with --lower-case?
My understanding is that we need two very different files, one that is used for upper case maps (the default if no --lower-case option is given)
and another one that has no expand rules but places the special characters when they should belong when sorting.

I also think that the conversion to upper case in mkgmap should be done using the content of the given codepage instead of the constant Locale.english.

Does that make sense?
Gerd

________________________________________
Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Gerd Petermann <GPetermann_muenchen at hotmail.com>
Gesendet: Dienstag, 25. April 2017 22:24:05
An: Development list for mkgmap
Betreff: Re: [mkgmap-dev] address search and the --lower-case option

Hi Andrzej,

thanks for the info. I am not sure if my change gives the correct sort seqence, I have to try that.

One question is why we have option --lower-case. My understanding is that we don't want
a map that shows Geissweg when OSM and the street signs say Geißweg. I assume there are
similar cases in other languages, too. The character µ is a minor problem as it appears only
a few times compared to ß, which appears very often in German road names.
It is also confusing when the device shows Geißweg but
a search for Geiß doesn't show the way. By the way, I have this problem also with unicode maps
on my Oregon. What bothers me is what the device does with my search value (at least
with an unpatched cp-1252.txt) :
When the search field is empty, it shows a key board with upper case characters A-Z ÄÖÜ and ß.
When I start to type Außer it switches to lower case after the A. When I press the "check" symbol
(v-shape in lower right corner) it shows the screen "no results found. Change search criteria".
When I go back to the dialog it shows AUßER, so it somehow thinks that the value has to be changed
to upper case. I wonder if this also happens with maps from Garmin, if not, there is probably a
flag somewhere to say if that is wanted or not.

Gerd

________________________________________
Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Andrzej Popowski <popej at poczta.onet.pl>
Gesendet: Dienstag, 25. April 2017 21:50:47
An: mkgmap-dev at lists.mkgmap.org.uk
Betreff: Re: [mkgmap-dev] address search and the --lower-case option

Hi Gerd,

if mkgmap converts "ß" tp "SS" when using upper-case, then your change
to cp1252.txt is good for both cases, isn't it?

I can see "ß" on Unicode version of City Navigator, but non-Unicode uses
"ss" instead. The same for demo version of Topo DE 2012, it is cp1252
and uses "SS". Maybe this is a good solution?

--
Best regards,
Andrzej

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