Question

I am using the Google map API V3 making a request with lat/lng, with the expectation of getting the full address data returned. However, my PHP program would fail to get, for example, the Zip Code returned sometimes. I did a var_dump of what’s being returned. I see an extra object element, which may be the cause I’m not sure. It’s entirely possible I don’t know everything about how Objects in PHP work too. Here is the var_dump output for the area of interest. The first example does indeed return the Zip Code to my PHP program making the request while the second one fails to do so and gives an error of “Trying to get property of non-object…”. Thanks in advance for taking a look on this and your useful comments.

This is the var_dump of $xml that is returned from Google Map API V3, which DOES NOT WORK and fails to return the zip code properly:

object(SimpleXMLElement)#1 (1) {
  ["Response"]=>
  object(SimpleXMLElement)#2 (3) {
    ["name"]=>
    string(24) "40.74005999,-73.99718229"
    ["Status"]=>
    object(SimpleXMLElement)#3 (2) {
      ["code"]=>
      string(3) "200"
      ["request"]=>
      string(7) "geocode"
    }
    ["Placemark"]=>
    object(SimpleXMLElement)#4 (5) {
      ["@attributes"]=>
      array(1) {
        ["id"]=>
        string(2) "p1"
      }
      ["address"]=>
      string(38) "136 W 17th St, New York, NY 10011, USA"
      ["AddressDetails"]=>
      object(SimpleXMLElement)#5 (2) {
        ["@attributes"]=>
        array(1) {
          ["Accuracy"]=>
          string(1) "8"
        }
        ["Country"]=>
        object(SimpleXMLElement)#8 (3) {
          ["CountryNameCode"]=>
          string(2) "US"
          ["CountryName"]=>
          string(3) "USA"
          ["AdministrativeArea"]=>
          object(SimpleXMLElement)#9 (2) {
            ["AdministrativeAreaName"]=>
            string(2) "NY"
            ["SubAdministrativeArea"]=>
            object(SimpleXMLElement)#10 (2) {
              ["SubAdministrativeAreaName"]=>
              string(8) "New York"
              ["Locality"]=>
              object(SimpleXMLElement)#11 (2) {
                ["LocalityName"]=>
                string(8) "New York"
                ["DependentLocality"]=>
                object(SimpleXMLElement)#12 (3) {
                  ["DependentLocalityName"]=>
                  string(9) "Manhattan"
                  ["Thoroughfare"]=>
                  object(SimpleXMLElement)#13 (1) {
                    ["ThoroughfareName"]=>
                    string(13) "136 W 17th St"
                  }
                  ["PostalCode"]=>
                  object(SimpleXMLElement)#14 (1) {
                    ["PostalCodeNumber"]=>
                    string(5) "10011"
                  }
                }
              }
            }
          }
        }
      }
      ["ExtendedData"]=>
      object(SimpleXMLElement)#6 (1) {
        ["LatLonBox"]=>
        object(SimpleXMLElement)#8 (1) {
          ["@attributes"]=>
          array(4) {
            ["north"]=>
            string(10) "40.7414089"
            ["south"]=>
            string(10) "40.7387109"
            ["east"]=>
            string(11) "-73.9958332"
            ["west"]=>
            string(11) "-73.9985312"
          }
        }
      }
      ["Point"]=>
      object(SimpleXMLElement)#7 (1) {
        ["coordinates"]=>
        string(24) "-73.9971822,40.7400599,0"
      }
    }
  }
}

The above has these errors:

PHP Notice:  Trying to get property of non-object in try.php on line 38
PHP Notice:  Trying to get property of non-object in try.php on line 41

Here is the PHP code for those lines:

$status = $xml->Response->Status->code;
// Country
$country = $xml->Response->Placemark->AddressDetails->Country;
$country_code = $country->CountryNameCode;
$country_name = $country->CountryName;

// Address
$address_line = $xml->Response->Placemark->address;

// Street address
$Locality = $country->AdministrativeArea->Locality;
// var_dump($Locality);
$street = $country->AdministrativeArea->Locality->Thoroughfare->ThoroughfareName;
$city = $country->AdministrativeArea->Locality->LocalityName;
$state = $country->AdministrativeArea->AdministrativeAreaName;
$zip_code = $country->AdministrativeArea->Locality->PostalCode->PostalCodeNumber;

Line 41 is the last line of code with the $zip_code, and line 38 is the line of code which begins with $street.

You will notice the above contains a [“SubAdministrativeArea”]=> which the working example below does not. Does this matter?

object(SimpleXMLElement)#1 (1) {
  ["Response"]=>
  object(SimpleXMLElement)#2 (3) {
    ["name"]=>
    string(24) "40.74445606,-73.97495072"
    ["Status"]=>
    object(SimpleXMLElement)#3 (2) {
      ["code"]=>
      string(3) "200"
      ["request"]=>
      string(7) "geocode"
    }
    ["Placemark"]=>
    object(SimpleXMLElement)#4 (5) {
      ["@attributes"]=>
      array(1) {
        ["id"]=>
        string(2) "p1"
      }
      ["address"]=>
      string(38) "317 E 34th St, New York, NY 10016, USA"
      ["AddressDetails"]=>
      object(SimpleXMLElement)#5 (2) {
        ["@attributes"]=>
        array(1) {
          ["Accuracy"]=>
          string(1) "8"
        }
        ["Country"]=>
        object(SimpleXMLElement)#8 (3) {
          ["CountryNameCode"]=>
          string(2) "US"
          ["CountryName"]=>
          string(3) "USA"
          ["AdministrativeArea"]=>
          object(SimpleXMLElement)#9 (2) {
            ["AdministrativeAreaName"]=>
            string(2) "NY"
            ["Locality"]=>
            object(SimpleXMLElement)#10 (3) {
              ["LocalityName"]=>
              string(8) "New York"
              ["Thoroughfare"]=>
              object(SimpleXMLElement)#11 (1) {
                ["ThoroughfareName"]=>
                string(13) "317 E 34th St"
              }
              ["PostalCode"]=>
              object(SimpleXMLElement)#12 (1) {
                ["PostalCodeNumber"]=>
                string(5) "10016"
              }
            }
          }
        }
      }
      ["ExtendedData"]=>
      object(SimpleXMLElement)#6 (1) {
        ["LatLonBox"]=>
        object(SimpleXMLElement)#8 (1) {
          ["@attributes"]=>
          array(4) {
            ["north"]=>
            string(10) "40.7458050"
            ["south"]=>
            string(10) "40.7431070"
            ["east"]=>
            string(11) "-73.9736017"
            ["west"]=>
            string(11) "-73.9762997"
          }
        }
      }
      ["Point"]=>
      object(SimpleXMLElement)#7 (1) {
        ["coordinates"]=>
        string(24) "-73.9749507,40.7444560,0"
      }
    }
  }
}

And here are the lines of code used to output which the $zip_code is blank for the first example, while with the second one it does work as expected.

echo "===================================\n";
echo "Status code is: " . $status . "\n";
echo "address line is:" . $address_line . "\n";
echo "=+=+=" . "\n";
echo "street is: " . $street . "\n";
echo "city is: " . $city . "\n";
echo "state is: " . $state . "\n";
echo "zip code is: " . $zip_code . "\n";
echo "country code is: " . $country_code . "\n";
echo "country name is: " . $country_name. "\n";

The different locations used in this example are both in New York City. I don’t know why one is working while the other is not, expect I see it’s returning the [“SubAdministrativeArea”]. Shouldn’t the Google map API V3 return the same format of information for the same area? Is this even a factor in the problem I’m having? Am I not handling the objects and elements correctly? If so, please enlighten me because I am stuck at this point.

Or should I be checking for two different situations which might be returned (or more?) by the Google map API V3? Thanks!

Answer 1

You will notice the above contains a [“SubAdministrativeArea”]=> which the working example below does not. Does this matter?

Yes it matters.

Shouldn’t the Google map API V3 return the same format of information for the same area?

Some elements of the answer will always be present at the same place in the result tree but some others depend on the request. I can’t help you more on this as I never understood why there was sometimes more sublevels even if requests were very similar…

Is this even a factor in the problem I’m having?

Yes, because you can’t rely on a fixed result structure.

Should I be checking for two different situations which might be returned (or more?) by the Google map API V3?

Another solution can be to use an other library than SimpleXML to handle the result, like DOM, which has functions to find children through a tree, like DOMElement::getElementsByTagName. Getting values needs a bit more coding than with SimpleXML but this way you don’t need to check if there is a SubAdministrativeArea level or not.

I hope it helps.