Frequently Asked Questions (FAQ)

Geocoding

General

Q: For what countries does AddressDoctor supply Geocodes?
A: The AddressDoctor Geocoding Service geocodes addresses for the following countries: Andorra, Austria, Belgium, Canada, Croatia, Czech Republic, Denmark, Finland, France, Germany, Gibraltar, Greece, Hungary, Italy, Liechtenstein, Luxembourg, Monaco, Netherlands, Norway, Poland, Portugal, San Marino, Slovakia, Slovenia, Spain, Sweden, Switzerland, United Kingdom, United States.

Q: Which AddressDoctor products provide geocoding functionality?
A: At present, the AddressDoctor batch and interactive Web Services provide geocoding functionality. You may geocode your addresses using the Data Quality Center or by creating your own application to access the web services. AddressDoctor for Excel and the AddressDoctor Enterprise Suite will follow.

Q: What am I allowed to use the geocodes provided by AddressDoctor for?
A: You may use the geocoded addresses for internal applications only. It is not allowed to use the data for internet applications or to redistribute them to third parties. If you plan to do so, please contact us at sales@addressdoctor.com

Q: Are the reference data bases for address cleansing and geocoding identical?
A: No, the reference databases are not identical. The reference databases are designed for their specific purposes and thus are provided by different organisations, and differ in their design, data format and contents.

Q: How frequently is the reference database updated?
A: The reference data for geocoding is updated semi annually.

Q: What Coordinate System are the coordinates in?
A: Addresses delivered by AddressDoctor are assigned coordinates of the World Geodetic Coordinate System of 1984 (WGS84). These coordinates are in decimal degrees.

Technicial

Q: Are addresses interpolated or referenced exactly to rooftop?
A: If a geocoded address contains the value ADD in the field OUT_GEOAccuracy, it is an interpolated house number. This means, the exact coordinates for the address are not contained in the reference database. Instead, the position of a street and the range of house numbers of this street are known. Then, the address is interpolated and offset to the proper side of the street.

Q: Is the geocode set on the middle of the streets or is it offset?
A: If an address is geocoded to rooftop, it is offset from the center axis of the street.

Q: Some of my addresses were not geocoded. What is the reason?
A: There are a number of possible reasons, why an address was not geocoded. They are written into the field OUT_GEOStatus. Possible values are:
0:    Geo coordinates are not provided, because you have no more
       geocoding transactions left.
1:    Geo coordinates are not provided, because geo coding is not
       available for this country.
2:    Geo coordinates are not provided, because the Validation Status
       was not V or C.
3:    Geo coordinates are not provided, because geo coding
       reported a no match.
4:    Geo coordinates are provided. The field OUT_GEOAccuracy
       describes the accuracy of the coordinates.

Q: What is the meaning of the field OUT_GEOStatus?
A: Please refer to the question above.

Q: To what detail level are addresses geocoded?
A: Where possible, addresses are geocoded to rooftop level. If this is not possible, they may be geocoded to the street, next fallback is center of a zip code or a locality. The detail level is written to the field OUT_GEOAccuracy. Possible values are:

ADD: The address was geocoded
STR: The Center of the street was geocoded
ZIPCD: The Center of a suburb within the postcode was geocoded
ZIPC: The Center of the locality within the postcode was geocoded
ZIP: The Center of the postcode was geocoded

Q: What is the meaning of the field OUT_GEOAccuracy?
A: Please refer to the question above.

Q: How can I calculate the distance between two geo-coordinates?
A: Calculation of a distance between two geographical points in WGS84

It is very complicated to calculate the exact distance between two geographical coordinates since different projections as well as the oblateness of the earth has to be considered. But in most cases a simple formula will help as long the distance is not too small and the points are not too close to the poles.

You will need WGS84 geo-coordinates in decimal degree (not in degree-minutes-seconds like N 49° 29.296 E 008° 27.722). All geo-coordinates provided by AdressDoctor are in decimal degree.

At first your geo-coordinates need to be transformed into a radian measure. To do this simply multiply the latitudes and longitudes by π/180 or use in Excel =radiant(X) and = radiant(Y).

You will get the approximate air-line distance with following formula:

d=R*arccos(sin(X2)*sin(X1)+cos(X2)*cos(X1)*cos(Y2 – Y1))

Earth radius R = 6378 km

Example:

1. Lisbon, Portugal:
   x-coord: 9.136523757581143;
   y-coord: 38.744916875859985
2. Arnheim, Netherlands:
   x-coord: 5.962115675929862;
   y-coord: 51.98395045710915

Longitude/Latidude	Decimal Degree	Radiant
X1	9.136523757581	0.15946242
Y1	38.744916875860	0.67622637
X2	5.962115675930	0.10405855
Y2	51.983950457109	0.90729109

Distance:

d=R*arccos(sin(X2)*sin(X1)+cos(X2)*cos(X1)*cos(Y2 – Y1))

d=R*arccos(sin(0.10405855) * sin(0.15946242) + cos(0.10405855) *
    cos(0.15946242) * cos(0.90729109 – 0.67622637))

d=1503 km