Can I get the google geocoder to tell me when a location can't be found, instead of just picking the center of a city?

Question

I'm working with the google maps API, and testing a section which geocodes all the addresses in a database which do not have coordinates, then generates a report of which were successful, and which failed.

If any of the locations couldn't be found, it should put a form at the top of the page to allow the user to either modify the address or specify coordinates.

I know that the geocoder can call back my code with the G_GEO_UNKNOWN_ADDRESS status code, but it never uses it. I put fake addresses into the database and got this:

The coordinates of 1337 Rawrmander Rd.
Were successfully set to:
    latitude:   49.170171
    longtitude: -123.136579

The coordinates of 5678 Imaginary Lane
Were successfully set to:
    latitude:   49.170171
    longtitude: -123.136579

It just gave back the center of the city (and continues to do so no matter what the address is) instead of calling it an unknown address.

This is how I call the geocoder:

//in a for loop
setTimeout( "geocoder.getLocations(\"" +
    //address to send to google
    values[i]['house'] + " " +
    values[i]['street'] + " " +
    values[i]['streetType'] + ", " +
    "Richmond, BC, Canada\", " +
    //google returns to this function asynchronously
    "function(reply) { handleReply(processItem++, reply); } );"
    , 
    callTimeout);
callTimeout += 220;

I tried changing "Richmond, BC, Canada" to just "Richmond" in hopes that it would not know which city to pick and then return an unknown address, but instead it just picked the middle of Richmond, VA.

Does anyone know a way to "hint" at google to give me an unknown address instead of just picking anything?

Answer 1

Check the coordinates of the address you have on hand, eg: "1234 Imaginary St, Vancouver" and then check the coordinates of just the city: "Vancouver". If they're the same, there's a problem. Unless they are living right in the very centre of town, that'd be a good indication the address doesn't work.

Answer 2

I think what you are looking for is the Accuracy Value. When you run a geocode, look at the accuracy value that comes back. Or are we talking about different things?

For example: Using the address you provide (5678 Imaginary Lane) I get the following:

200,4,44.9774820,-93.2643510

versus using a real address (701 1st Ave N) the result is:

200,8,44.9782860,-93.2760830

Note the second value there (4=TownLevel vs 8=AddressLevel). Looking for Imaginary,MN I'm able to get the Accuracy down to 2=RegionLevel. I was able to get a 602=G_GEO_UNKNOWN_ADDRESS response (accuracy of 0=Unknown) when I looked for Imaginary,XX.

602,0,0,0

Answer 3

The Geocoder will return the status code of 602 when it really can't find a location. More often than not though - it will just take a shot in the dark and give you a result. The accuracy value will not tell you that you just got a shot in the dark. It only tells you whether your result is a country, city, address, etc. Unfortunately, there doesn't seem to be a way around this.