Capabilities of GeoCoder#

What information does GeoCoder provide?#

GeoCoder will provide the following information for a valid ZIP and Plus4 combination:

  • Latitude

  • Longitude

  • County FIPS

  • County Name

  • Census Block

  • Census Tract

  • Place Code

  • Place Name

  • CBSA Information

  • CBSA Division Information

  • Time Zone

GeoCoder can also compute the distance and bearing between two latitude/longitudinal sets.

What type of Geodetic system does GeoCoder use?#

WGS-84 is the geodetic system used in the object’s data to determine bearing and distance. WGS-84 is an earth fixed global reference frame, including an earth model.

This standard is used by the European Air Traffic Control and is a standard mapping reference used by many countries.

How do I use GeoCoder as a Distance Calculator?#

GeoCoder can be used to determine the distance between two points. For this functionality, you only need the ZIP and Plus4 from the two points. That can be obtained using Address Object. Once you have that, run GeoCoder on those two locations and extract the latitude and longitude. Then, simply pass those two sets of latitude/longitudes into the ComputeDistance() method, and a distance of miles will be returned to you.

geoObj.GeoCoder(Location1ZIP, Location1Plus4)
Lat1 = geoObj.latitude
Long1 = geoObj.longitude

geoObj. GeoCoder(Location2ZIP, Location2Plus4)
Lat2 = geoObj.latitude
Long2 = geoObj.longitude

Miles = geoObj.ComputeDistance(Lat1,Long1,Lat2,Long2)

This can be used for applications like a Dealer Locator where you have a point of origin and several dealer locations. You would compute the distance from the origin to each dealer location and pick the one with the smallest distance.

How accurate is GeoCoder?#

The latitude and longitude data that GeoCoder uses is based on the Plus4. So, GeoCoder Object by itself is accurate to the Zip+4. The GeoPoints add-on data for the object appends more precise lat/long coordinates to the ZIP+4 + Delivery Point - the 11-digit level of an address or parcel. If neither the 9-digit or 11-digit lat/long coordinates are available, GeoCoder Object will return coordinates based on (1) the ZIP+2 or (2) the 5-digit ZIP.

GeoCoder Object Setup#

What Data Files are used by GeoPoints?#

The following are the required data files used by GeoPoints:

  • All GeoCoder Data Files

  • mdGeoCode.db3

What Data Files are used by GeoCoder?#

The following is the required data file used by GeoCoder:

  • mdGeoCode.db3

What should I do when installing GeoCoder?#

When installing GeoCoder, always read the changes.txt file on the root of the CD. It will contain any changes that were made since the last release of GeoCoder. Some changes may require rewriting or recompiling your application, so it is important to always check the changes file.

What are the differences between the COM and standard version of GeoCoder?#

There are essentially no differences in the underlying code for the COM version and the Standard version of GeoCoder Object. The COM version has a COM interface layer used to communicate between your code and GeoCoder Object and is supported by many different languages. The Standard version of GeoCoder Object, and it is an unmanaged dll that must be included into your program which eliminates the extra latency created by the COM layer.

GeoCoder Object Usage#

How is Logging Data Handled?#

GeoCoder Object will use port 443 to send traffic to our servers. We encrypt and decrypt the traffic ourselves.

The object will make a call out to this domain:


Currently, the logging data is sent to However, we reserve the right to change the IP Address in the future. Please reference our IP ranges and allow them to future-proof your firewall access.

  • IP Address Information

What inputs are necessary for Geocoding?#

The minimum input is a ZIP Code. If you enter a ZIP Code, GeoCoder will give you the latitude and longitude of that ZIP Code based on population density. (Closest to the most dense area of the ZIP Code) To get plus4 accuracy, you must enter both a ZIP Code and a plus4.

How do I determine the bearing of a location?#

GeoCoder can also compute the bearing of a location from an origin location. Bearing is the clockwise angle of the destination in reference to the origin with 0° being North, 90° East, 180° South, 270° west. Similar to ComputeDistance, the ComputeBearing method takes in two sets of latitude/longitudes. The bearing is returned as a degree ranging from 0 to 360.

geoObj.GeoCoder(Location1ZIP, Location1Plus4)
Lat1 = geoObj.latitude
Long1 = geoObj.longitude

geoObj. GeoCoder(Location2ZIP, Location2Plus4)
Lat2 = geoObj.latitude
Long2 = geoObj.longitude

Direction = geoObj.ComputeBearing(Lat1,Long1,Lat2,Long2)


What is GeoPoints?#

GeoPoints is a GeoCoder add-on that enables rooftop GeoCoding, as opposed to the standard Zip+4 level of accuracy.

To activate GeoPoints, simply set the path to the GeoPoints Data Files:

geoObj.PathToGeoPointDataFiles = dFILELOC;
geoObj.GeoPoint("Zip", "Plus4", "DPC");

The data for GeoPoints is provided by Tele Atlas.

Also, in order to make use GeoPoints, you will need to use a different License Key from GeoCoder. Contact your Sales Representative for a GeoPoints License Key: 1-800-MELISSA ext. 3

What is GeoCoding?#

GeoCoding is the process that assigns a latitude-longitude coordinate to a valid ZIP+4. Once a latitude-longitude coordinate is assigned, the data can be used for distance mapping or in a spatial search.

Melissa Data’s GeoCoder Object will attempt to return the coordinates of an address based on the ZIP+4® code for that address. This (Plus4) centroid is usually compact and averages 9 households. In addition to Latitude and Longitude, the object returns Census Data such as Census Blocks, Tracts, County Names and FIPS numbers.

The Latitude returned by GeoCoder will always be a positive latitude as all US ZIP CodesTM are situated north of the equator. The Longitude will always be a negative longitude as all US ZIP Codes are all situated west of the Greenwich meridian.

There are also methods like Compute Distance and Bearing which can be used to Calculate the distance between two Plus4s and their general direction.

Update Frequency#

How often is GeoCoder updated?#

GeoCoder is released as quarterly updates (Spring, Summer, Winter, Fall) and is valid for 9 months after its release.