Maybe the word ‚place names‘ wasn’t clear enough, sorry. Let me clarify: I want to search in the NAMES ON THE MAP.
@mbe57 Thanks for the answer! I think I understand it somewhat, but not fully. Please forgive me for asking some more questions.
1. As I was told by the maker of one app, mapsforge is not only a map-format but also a set of (java) routines to handle these data. Apperently – at least that is what I make of it – there is no routine to ‚extract‘ the placenames from the map file and that is the reason why (apparently) no app makes them searcheable. Does this make sense to you?
2. Thanks for the tip about Locus, an app I don’t know. Some apps (Cruiser, Cartograph and Locus as well, probably) can load the separate POI files OSM provides and these can be searched. The result is not at all what I mean (see below) but I point to the principle: if a (huge) POI overlay can be quickly searched, then why not ‚convert‘ the names on the map to a POI file? It would at least be a ‚universal format‘. Maybe it could even be made ‚on the fly‘ but if not they could be made available for download. Or a utility could be made to extract the names and write a POI file. (I’m just phantasising now.)
@tobias I don’t know Oruxmaps, but I tried Cruiser and Cartograph; both on my laptop and on my phone. Searching the POI overlay is indeed fast. BUT for searching a name on the map it is almost totally unuseable.
The problem is that these POI files a) do not contain all the placenames on the map and b) contain a myriad of names which are NOT on the map (restaurants, businesses etc.)
Moreover, the search mechnisms for both apps I tried are not at all geared toward this purpose. Not only very time consuming to use, but also giving either hundreds of hits (not on the map) or no hits at all when you don’t know which ‚categories‘ to search for (town? or is it a city? or a village?). Rivers and waterways do not even have a category! (And are not in the POI overlay)
On the other hand, on-line services do a far better job. Backcountry Navigator uses ‚google location services‘ which works kind-of OK but doesn’t find all the names on the map; notably not (o irony) in nature reserves and backcountry areas. Cruiser can not connect to an on-line service. Cartograph does best in this respect as it allows connecting to the ‚OSM Nominatim‘ service which apparently contains the names on OSM maps. But (like Google) the request is not linked to the map I’m using so it finds names all over the world which can be a terrible hassle.
So, if the names are available on-line from ‚OSM Nominatim‘, why not off-line and per map? Hence my suggestions in my answer to @mbe57. Think of an old fashioned paper atlas: would you buy one without an extensive index at the back?