[Geocoding] holes in the nominatim search results

[Sarah Hoffmann]

Hi,

On Tue, Mar 29, 2016 at 02:23:48PM -0400, Allan Visochek wrote:
> Hey there,
> 
> I'm having trouble making sense of some gaps in the data I am getting from
> the nominatim search.
> 
> For a project that I am working on, I need to find the length of various
> streets. I've set up a program which does the following and works fine:
> 
> 1. Query the raw osm file for all way elements with a particular name.
> 2. For each element, iterate over the node reference tags and retrieve the
> longitude and latitude coordinates of each node.
> 3. Add the distances between each pair of consecutive nodes if they are
> within the boundaries of a particular city.
> 
> Again, this program works fine, I'd be glad to include the code if it would
> be helpful, but have left it out for now to keep things concise.
> 
> To save time, I have installed nominatim. My current method is to search
> for elements using the street name as a query and return the geojson for
> that element:
> 
> /search?q=Chapel+Street&format=json
> I've also tried:
> /search?format=json&street=Chapel+Street
> and I've tried this with a number of different streets.
> 
> The problem here is that a lot of segments of any particular street are
> left out. I have checked to verify that my local results are the same as
> those

Try to add a dedupe=0 to your parameters, possibly combined with a
limit=100. This should give you all the missing segments. You will
still have to combine them yourself. There is a feature request open
to combine the segments already in the server but so far nobody has
found the time to implement it:
https://github.com/twain47/Nominatim/issues/332

Kind regards

Sarah