[mkgmap-dev] Index and equally named cities

Mon Jul 11 01:51:06 BST 2011

Dear steve,

Here's a bit of explanation from one of our colleagues.

> So can you explain exactly what is better and worse between the
> city-region-index branch r1867 and r1870.

> Do the different "San Fernando's" have different regions? If not how do
> you tell them apart?

---------- Forwarded message ----------

tested on "Find Places - City" of Mapsource v6.13.7
have not tested mkgmap r1870

Note: there are 7 San Fernando towns and cities in different provinces
in philippines.osm

-We don't have (and we don't use) is_in:region in philippines.osm (at
the moment)
-We primarily use is_in:state to tag the 'province'  of a specific town or city
-There are no 2 similarly-named city or town within the same province
in Philippines.
-But there are hamlets & villages that may have the same name as town
or city within the same province.
-Since villages & hamlets are treated as 'small cities or towns' by
hex code assignments in Garmin, we demoted all villages and hamlets to
ordinary Amenity-POI's to prevent complications with similarly-named
cities.

OBSERVATIONS on mkgmap r1867: It can index and differentiate
"similarly named towns & cities" if and only if:

1. we remove all country tags by:   name=* { delete is_in:country }
and replace it with
   place=* & is_in:state=*
   add is_in='${is_in:state},,Philippines'
  (eg. essential tags for mkgmapr1867---> name=San Fernando
place=city   is_in='Pampanga,,Philippines')

2. is_in='<province_name>,<blank_space>,Philippines'  ---->magically
assigns all town/s and cities to their respective Provinces in the
Philippines.
   BUT, it has a conflict with is_in:country (which tends to
disassociates the POI from the town & province). This was discovered
by trial & error. No explanation for this weird behavior.

3. is_in='${is_in:state},,Philippines' on city-POI makes that city
'unique' (within a given radius. not sure of the exact figure, but it
looks like 30km).
   All amenity-POI within that given radius are associated and
searchable under that city, as long as you tag said amenity with
addr:city

4. is_in:state on a city-POI has no effect on indexing, unless we
combine it with is_in='${is_in:state},,Philippines'
    addr:state on an amenity-POI has no observed effect on indexing.

5. the 'address-search' on works on older Garmin model such as marine
handhelds, outdoor models and nuvi 255W

6. the 'address-search' does not work on Nuvi 1310 (and most 4digit
models) - No Map Data Available

OBSERVATIONS on mkgmap-city-region-index-r1984.jar and all the latest mkgmap

1. under the same condition as above, the "address-search" on works on
Nuvi 1310, but missing similarly-named cities.
    (eg. only 2 San Fernando appears - which are located on separate tile)

On Sun, Jul 10, 2011 at 5:32 AM, Steve Ratcliffe <steve at parabola.me.uk> wrote:
>
> On 07/07/11 09:35, maning sambale wrote:
> > Testing this version,
> > Uploading via mac mapinstall is a bit longer but not too long
> >
> > I only get two "San Fernando"s that are in a separate tile.  The other
> > "San Fernando"s within one tile is not included in the search results.
>
> So can you explain exactly what is better and worse between the
> city-region-index branch r1867 and r1870.
>
> Do the different "San Fernando's" have different regions? If not how do
> you tell them apart?
>
> ..Steve
> _______________________________________________
> mkgmap-dev mailing list
> mkgmap-dev at lists.mkgmap.org.uk
> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev

-- 
cheers,
maning
------------------------------------------------------
"Freedom is still the most radical idea of all" -N.Branden
wiki: http://esambale.wikispaces.com/
blog: http://epsg4253.wordpress.com/
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