[mkgmap-dev] Performance of POI search on the Device

Sun Jul 19 07:39:56 BST 2020

Hi all,

I still try to understand why the existence of a (transparent) overlay map can slow down the search for POI. It seems the more tiles we have in the overlay
the longer the delay. So, it looks like the Oregon performs a sequential search over all tiles in the overlay map. It seems to ignore a global index in that map,
but, as Franco found out, it might stop earlier / work faster when the overlay map contains a few POI.

My 1st assumption was that the transparent flag makes it difficult for the device to find out if the tile contains any data that may be relevant as it doesn't contain the 0x4b polygon. I tried with a semi-transparent map (0x4b polygon written and transparent flag set). Didn't improve anything.
So, another idea is that the POI with address info change the content of the LBL file header because e.g. the list of countries is filled.
Maybe the device checks this.
Looking at this now...

Gerd

________________________________________
Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von franco_bez <franco.bez at web.de>
Gesendet: Dienstag, 2. Juni 2020 18:32
An: mkgmap-dev at lists.mkgmap.org.uk
Betreff: Re: [mkgmap-dev] Performance of POI search on the Device

Hi Gerd,

here's the bondary-layer with x-center-poi-type=0x2f01
It slows down the search to the same extent as the other poi-types do.
The option does not seem to have any impact.
http://files.mkgmap.org.uk/download/477/dach_boundary_gmapsupp.img
<http://files.mkgmap.org.uk/download/477/dach_boundary_gmapsupp.img>
Ciao,
Franco

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