Finding entrances

[graue]

Hi Nominatim community,

I am looking for a way to, given a park (for example https://www.openstreetmap.org/relation/13070397), find a list of its entrances (entrance=*) and/or trailheads (highway=trailhead). As a first pass, I figured I would use the park's bounding box, and this feature from the search docs:

When bounded=1 is given and the viewbox is small enough, then an amenity-only search is allowed. Give the special keyword for the amenity in square brackets, e.g. [pub] and a selection of objects of this type is returned. There is no guarantee that the result returns all objects in the area.

My application could then filter to within the park's polygon with some tolerance. But trailheads and entrances do not fit the amenity=* pattern. (Also, even for things that do, like amenity=drinking_water, I'm strangely not getting results on my own instance of Nominatim 5.2, even though I do on the public API.)

The use case is routing, similar to what is described in this blog post about entrance information, so I got excited when I saw that. But that presents two problems: 1) trailheads, for parks, are not exactly entrances, and 2) most of the parks I want to use this for are mapped as relations, not ways, and the blog mentions this feature currently only supports ways.

Is there any way Nominatim can find me all nodes with entrance=* or highway=trailhead tags within a geographic area?

[lonvia]

It looks like you are running your own instance of Nominatim. That means you can configure it to index entrances and trailheads and then search for them:

Firstly, you need a custom Lua import script with the extra objects:

local flex = require('flex-base')

flex.load_topic('full', {with_extratags = true})

flex.set_main_tags{
    highway = {trailhead = 'always'},
    entrance = 'always'
}

Reimport the database to get the new data.

Then you need special phrases to be able to find those items by type. Easiest here is to use the CSV import with --no-replace to add to whatever other special phrases you have. The CSV file should look something like this:

phrase,class,type,operator
trailhead,highway,trailhead,-
entrance,entrance,yes,-
entrance,entrance,main,-

Now the search [entrance] with a viewbox and bounded should give you the entrances. You should be aware though that Nominatim doesn't necessarily return complete lists because as a search engine it is tuned towards returning the best matches, not all of them. If you need complete lists of OSM objects with a certain tag in an area, then Overpass is the better tool.