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Searching for an address from coordinates

Posted: Fri Oct 07, 2016 7:27 am
by VPlachy
Hello,
I have a problem with finding addresses by coordinates. I use the function findLocation and coordinates are "49°34'21.1"N 13°34'44.8"E". When you try to search for an address that I coordinate the function returns twenty addresses, but all are at least three kilometers from the given coordinates, so it's unusable for me.

Image

What settings should I use? What function should I use?

Thank you
Vladimir

Re: Searching for an address from coordinates

Posted: Fri Oct 07, 2016 7:46 am
by Bernd Welter
Hello Vladimir,

here are some successful screenshots based on 2016.1 HERE maps. Which map do you use?
looking for about 10 hits
looking for about 10 hits
Without applying reverse serach options: just the closest hit
Without applying reverse serach options: just the closest hit
Best regards Bernd

Re: Searching for an address from coordinates

Posted: Mon Oct 10, 2016 7:07 am
by VPlachy
Hello Bernd,
I used test servers https://xlocate-eu-n-test.cloud.ptvgrou ... ws/XLocate

Best regards Vladimir

Re: Searching for an address from coordinates

Posted: Mon Oct 10, 2016 7:21 am
by Bernd Welter
Hello Vlad,

one parameter that causes a significant difference in this scenario is the ReverseSearchOption.FILTERMODE:
  • 0 - filter nothing
  • 1 - filter results where the streets have no name
  • 2 - filter streets without a name and duplicate street results
In the given scenario the data of the streets seems to be poor.
As you can see in the street/housenumber columns: these are empty. This is why they get filtered by the FILTERMODE==1.
As you can see in the street/housenumber columns: these are empty. This is why they get filtered by the FILTERMODE==1.
As far as I know the FILTERMODE==1 is the default which is driven by historical reasons (The parameter was invented with 1.8 after some complaints and the API had to response in the old style by default).

So I'm not sure whether this info resolves the issue. In the end you need better data, too.

Regards Bernd
The 2016.1H map produces a better result in this region. Though you still don't get housenumbers: the streetnames are not empty.
The 2016.1H map produces a better result in this region. Though you still don't get housenumbers: the streetnames are not empty.

Re: Searching for an address from coordinates

Posted: Mon Oct 10, 2016 7:42 am
by Joost
As far as I know the FILTERMODE==1 is the default which is driven by historical reasons (The parameter was invented with 1.8 after some complaints and the API had to response in the old style by default).
For some background on this, consider the following scenario's:
  1. You are getting the GPS data from a vehicle and want to lookup the street name the vehicle is on. The GPS signal however has an inaccuracy which sometimes causes the points to be on the wrong street (side street for example). We found out that when the xLocate was returning a street with no name, almost always the GPS inaccuracy causes the wrong street to be taken. Filtering out unnamed streets improves the result a lot.
  2. Parking lots and gas stations next to a highway often are unnamed streets. Many customers preferred that instead of a unnamed street to see the highway name. By filtering unnamed streets this could be achieved.