Gerd, can you explain how addresses are stored in the Garmin maps? Are they millions of individual nodes, or "interpolation ways" with a start and an end? Are they just coordinates, or are they internally linked to a road in some way? Can it handle non-numeric house numbers? Understanding the "target data model" might help to assess all the possibilities we have in interpreting the data from OSM.

Colin

On 2015-03-01 09:42, Gerd Petermann wrote:

Hi all,

during the last days I've analysed the reasons for the error messages reported
by some of you. I came to the conclusion that I have to
- change the handling of addr:interpolation ways completely
- add code to detect the "random number" case earlier and - if detected -
use different methods to split the number intervals

Both are rather complex changes, so I'll need a few days to code this.

One open question for you:
How should we handle "missing" information?
If mkgmap finds the numbers 1,3,9,11,17  in that order on the left side
of a road called ABC, it can create different housenumber informations.
One could  be like "odd numbers from 1 to 17 on the left",
another could be a more complex sequence
1) "odd numbers from 1 to 3 on the left",
2)"odd numbers from 9 to 11 on the left",
3) "odd number 17 on the left"
A search for ABC 5 would either show a point between 3 and 9
or two entries with the numbers 3 and 9.
The latter tells you that OSM probably doesn't contain the
exact information and let's you decide where to search for ABC 5.

The trunk version tends to the simple info, while r3486
is more likely to produce the complex one.
I think trunk is better here, the complex case should only
occur if the "random number" case was detected.

Do you agree?

Gerd

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