I just found out the reason why my Christmas present wasn’t delivered. OSM gave me the wrong post code for the street in Amsterdam. Google gets it right.
The street that OSM shows on the map was correct, though, that’s why I wasn’t suspecting anything.
I just started evaluating OSM and found it to be a possible alternative to Google but now I wonder how such a mistake is possible and how often this happens. Is this a common issue? Is it country-specific? How can I report such errors if spotted?
We can try to find the culprit if you tell us this special street or a similar street next to it if the error comes there, too.
Then tell us what Postcode result you expected and what result you have got by what kind of OSM search engine. If you used the search feature from the main site osm.org then it is called http://wiki.openstreetmap.org/wiki/Nominatim
First: If you are Dutch then I can recommend the Netherlands subforum. Local knowledge should be there.
Second: not many postcodes (in NL) have been added to the OSM data base. If you look here (and press akkoord) you will see all buildings in the Netherlands (BAG database) . You will see that the Singerstraat has various postcodes but none of the above. My guess is that Nominatim tried hard to find a postcode near the Singerstraat but failed.I have a feeling that Nominatim is not allways correct. So far it is not an OSM issue but a Nominatim.
Some of the BAG data(including post code) has been added to OSM. See example. If in this case a postcode is incorrect then you can report this in openstreetbugs. See example of a house that hase been imported from the BAG source.
On the Netherlands subforum there is a thread about importing BAG data (closely related to postcode) which may be of help.
If postcodes (in NL) is very important to you I would not use OSM data but stick to Google. On the other hand there are many reasons to use OSM data. Not only because the data is available for everyone (try ask google for their data ) but also because in many cases OSM data is much better (cycleways, paths etc.)