[mkgmap-dev] What should be in the global index by default?

Wed May 10 09:39:35 BST 2017

Hi Andrzej,

thanks for the info. I also noticed the MD2 file before and have no idea what it contains, but
the name sounds to me like a short form of "MDR Version 2", so I also guessed that it is an index.
It seems to contain compressed data, at least I see almost no readable strings.
And yes, index in gmapsupp doesn't contain full name but lists containing the first 2 or 4 characters 
of names(MDR17). 
BTW: The search for cities (as POI) doesn't seem to search for sub strings as with the other POI types,
a search for amb will not find Hamburg or Bamberg, and city POI have their own list in MDR17.

I assume that older devices did not do that sub string search for POI names.
In that case they probably use the index. Maybe someone with a device older than - say -  8 years
can try that?

Gerd

________________________________________
Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Andrzej Popowski <popej at poczta.onet.pl>
Gesendet: Mittwoch, 10. Mai 2017 01:56:07
An: mkgmap-dev at lists.mkgmap.org.uk
Betreff: Re: [mkgmap-dev] What should be in the global index by default?

Hi Gerd,

I did some testing with map of Poland and nuvis 3540 and 1440. I have
looked for address, cities and POIs. On 3540 I get hints for each type
of search. On 1440 there are no hints. I don't know, if this indicate
the use of index. Maybe 3540 is simply more capable and can access data
in tiles faster.

In case of address and city, nuvi shows list of results before entering
a full name. I think it shows list, when there is a limited number of
results. When looking for a city, names in different regions are treated
as different hits, so list is longer than when searching for address.
This could be a cause for different behavior.

I think that index in gmapsupp doesn't contain full name, it is like 4
first characters or something. So even when using index, nuvi has to get
full name from tiles. This could cause search delay and could be the
reason for showing the hourglass icon.

With my very limited test, I didn't spot any problems. I have tested
gmapsupp.img created by mkgmap and by MapInstall. Both worked the same.
MapInstall adds another type of index to gmapsupp, it has extension MD2.
I don't know what it is for, maps work without it too.

--
Best regards,
Andrzej
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