Some of my addresses were not geocoded. What is the reason?

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.

Understanding Geocoding Status Values

• EGCU: Geocoding database not unlocked
• EGCN: Geocoding database not found
• EGCC: Geocoding database corrupt
• EGC0: No Geocode available
• EGC1..4: Reserved for future use
• EGC5: Geocode with postal code level accuracy
• EGC6: Geocode with locality level accuracy
• EGC7: Geocode with street level accuracy
• EGC8: Geocode with house number level accuracy (interpolated approximation)
• EGC9: Reserved for future use

How can I calculate the distance between two geo-coordinates?

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 as 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 ?/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 k

Example:

Lisbon, Portugal:

x-coord: 9.136523757581143
y-coord: 38.744916875859985

Arnheim, Netherlands:

x-coord: 5.962115675929862
y-coord: 51.98395045710915

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

What is the meaning of the field OUT_GEOAccuracy?

The field OUT_GEOAccuracy describes the accuracy of the coordinates.

To what detail level are addresses geocoded?

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:

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

What is the meaning of the field OUT_GEOStatus?

The field OUT_GEOStatus describes the possible reasons, why an address was not geocoded. 

Is the geocode set on the middle of the streets or is it offset?

If an address is geocoded to rooftop, it is offset from the center axis of the street.

How frequently is the reference database updated?

The reference data for geocoding is updated as often as four times a year.

For what countries does AddressDoctor supply Geocodes?

AddressDoctor geocodes addresses for the following countries:

• Andorra
• Australia
• Austria
• Belgium
• Brazil
• Canada
• Croatia
• Czech Republic
• Denmark
• Estonia
• Finland
• France
• Germany
• Gibraltar
• Greece
• Holy See
• Hungary
• Iceland
• Italy
• Latvia
• Liechtenstein
• Luxembourg
• Malta
• Mexico
• Monaco
• Netherlands
• New Zealand
• Norway
• Poland
• Portugal
• San Marino
• Singapore
• Slovakia
• Slovenia
• Spain
• Sweden
• Switzerland
• Turkey
• United Kingdom
• United States

Are addresses interpolated or referenced exactly to rooftop?

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.