Where the streets have no name - strange reverse geocoding

[Bernd Welter]

Hello together,

within PTV consulting we recently faced a customer's request that which wasn't that obvious to be resolved.
He performed a reverse geocoding with xLocate.findLocation (more or less default parameters) and wondered why the result didn't return the streets that are located much closer than the ones that are part of the result:

default filters enabled (to be more precise: filters not disabled)

The red circle is the input coordinate and the crosses and flags are the result hits. The customer extpected the white roads nearby to be part of the result.

Now with a different parameter setting it is possible to retrieve those close streets as well:

Filters disabled: ENGINE FILTERMODE = 0

The cause for this behaviour is a historcal one and it is related to the engine profile parameter engine.filtermode / request parameter ENGINE_FILTERMODE:

Here is it's specification taken from the default profile:
Specifies the way the xLocate will filter the reverse locating results. Possible values are:

• 0 - filter nothing
• 1 - filter results where the street has no name
• 2 - filter streets without a name and duplicate street results.

We added this filter somewhere on the past roadmap and as we are expected to be backwards compatible the default value of the setting is "apply the filter". So while normally the default value of a filter is "filter nothing" and you'd have to activate the conditions this filter is enabled by default and if you don't want to use it you have to disable it.

But: once you know this behaviour it is quite easy to resolve.

Best regards from Germany,
Bernd