Geocoding is the process by which we represent the location of an address on a
map. Any data that has to do with a specific place on Earth can be geocoded if
you follow a few guidelines.
How does geocoding work?
When you submit location data, the CDRSS application's computer looks through
millions of address records to find your location. Two sets of data are scanned
to ensure accuracy. One dataset is produced by Geographic Data Technology, Inc.
(GDT). The other is ArcIMS RouteServer data, produced by Environmental Systems
Research Institute (ESRI). Within seconds, potential addresses are returned.
The geocode process returns results based on a candidate score scale ranging
from 0 to 100. Returned results can be an absolute match, a partial match or no
match. An absolute match is a location that matches the desired address with a
score of 100. A location with a score less than 100 is a partial match.
Finally, if no results are returned for a specified address, then no match was
found during the geocode process.
The geocode process functions behind the scenes, without interfering with the
flow of data entry, unless an absolute match is not found. In this case, you
will be prompted to make a selection from the returned partial matches. The
returned partial matches can include all possible address matches as well as the
center of a zip code, the center of a county, or the center of a municipality.
In some instances, the geocoding function cannot find the street address. For example,
in the case of new streets and new housing developments, the coordinates for that location
may be too new to appear in the geocoding data. Therefore, CDRSS allows the user to view
the map and place a point on the map corresponding to the address, and allows the user to
label that point appropriately. To save a custom location within the database,
the user must click on the save icon.
What information do I need to geocode my data?
In order to geocode you must have an address. In CDRSS,an address contains the
fields 'street', 'apartment', 'city', 'state', 'zip', 'NJ county', and
Avoid entering P.O. Box addresses into CDRSS. At the very best, you will only be
able to locate the zip code in which the P.O. Box falls. Remember, a patient may
not live in the same zip code, town, or county as their P.O. Box.
An address may be unsuitable for geocoding based upon how it is entered into
CDRSS. The two examples below illustrate a correct entry as well as a common
In the example above, notice that the apartment letter, in this case 'A',
is entered in the 'Apartment' field, and NOT the 'Street' field.
In the example above, the address format is incorrect because
the apartment letter is listed in the 'Street' field and not the 'Apartment'
field. CDRSS will find a partial address match, but due to the fact that
the geocoding process standardizes the street address, the apartment
letter will be deleted from the case information. To avoid this situation,
always ensure that suite or apartment numbers are entered in the
What if I don't have all of this information?
In many cases addresses can be geocoded without zip codes or municipality names.
Be aware, however, that the result will not be as accurate. For example, a
location geocoded by zip code alone will appear at the middle of that zip code
regardless of its actual location within the zip code.
As a rule, the less information you enter the more likely you are to have more
than one location option returned. For example, if you knew that 15 Main St. was
in Mercer County, but you did not know the municipality or the zip code, your
options would be to place a point in the middle of Mercer County, or to choose
not to geocode the location, or to choose to place a custom location on the map.
When you are missing information (in this case the
City and Zip), your only options will be to place a
point in the center of the county or to leave the
address off of the map.
In cases where you have only the street name and number, but not the city,
state, zip code, municipality, or county, the CDRSS system will choose NOT to
geocode the address. Instead, a screen indicating your case has been added to
the database will appear.
Occasionally you may only have city and zip code information. In this situation,
the geocoding process will elect to geocode by zip code since that is usually
the more precise geographic entity. In some cases a zip code may cover more than
one municipality or county. Be aware that the geocoding process will not know
which municipality or county is correct, requiring you to manually select the
correct option to avoid the city information being reset to "Unknown".
IMPORTANT POINTS TO REMEMBER
* It is impossible to geocode by Zip+4.
* Geocoding cannot locate every address in existence. This is due to a variety
of problems. For example, some addresses may be too new to be in the database
used for geocoding.
* Geocoding cannot show you where an apartment is located within a building.
It will show you where the building is located.
* It can't geocode an address range. For example, Company Z at 200-400 Oak St.
will not be found. My suggestion is to go for middle ground and call the
location 300 Oak St.
* Some addresses are simply missing from the address geodatabase. In this case
you can place the address as close as possible to the actual location,
normally by zip code, municipality, or county or; leave the location off of the map
* Remember, a mailing address might be different than a street address. If you
want to know the location of the street address, you need to make sure that you
enter it correctly. The geocoding software can't tell the difference.
* Geocoding is not perfect. A point may not fall exactly where you think it
should, but it will invariably be close.
* Check your spelling - incorrectly spelled addresses will not be found by the
What will my geocoding results look like?
If the geocoding process finds an exact match for the address you entered, you
will not be notified of any geocoding action. The address information will be
geocoded and attached to the case information.
If the geocoding process finds one or several partial matches for the address
you entered, you will be directed from the case data entry screens to a geocode
screen in order to review the returned geocoded locations. The returned
geocoded location matches will include at minimum a center of zip code, a center
of county, and a center of municipality option, and may also include several
potential street address matches. You, the user, must then choose the most
appropriate option. Once satisfied, you can continue by selecting the 'Submit'
button. A screen confirming that the address has been geocoded and assigned a
case number will appear.
This screen will allow you to choose the most appropriate option. Once you click
the 'Submit' button the following screen will appear to confirm that your geocoded case was
successfully added to the CDRSS database.
It is important to recognize that the geocoding process will override some of
the information you entered on the case data entry screen based upon your action
when provided with a list of partial matches. The following table explains the
results of different geocoding options.
If you choose to geocode a partial match...And the county/municipality/zip
code matches your original inputAnd the county/municipality/zip code does
not match your original input by County Centroid The county and municipality
information will be accepted as originally entered The county information will
be accepted and the municipality information will reset to 'unknown'
by Municipality Centroid The county and municipality information will be
accepted as originally enteredThe municipality information will be
accepted and the county information will be recalculated
by Zip Code Centroid The county and municipality information returned by
the geocoding software will override your original input The county and
municipality information returned by the geocoding software will override
your original input by Street AddressThe county and/or municipality information
returned by the geocoding software will override your original input. The
county and/or municipality information returned by the geocoding software
will override your original input.
In some cases no address match will be returned. This situation occurs when the
address information entered was not complete enough or does not match any known
address in New Jersey. You may go back to re-enter address information or
choose to submit the entered data as-is. If you choose to submit the entered
data as-is, CDRSS will confirm that you have chosen not to geocode the address.
Upon clicking 'ok', a screen confirming that the case was successfully added to
the CDRSS database but was NOT geocoded will appear.
In the instance where the street information is known, but the geocoding service
does not find it, the user may choose to geocode to a custom location, referred to
as an X and Y coordinate on the map. Sample screen shots appear below to assist with
the custom location process.
What happens if I update a case?
If you update a case, but do not update any of the address information, the
geocoding process will not attempt to re-geocode the address. However, if you
change any of the address information, you will be prompted to re-geocode the
What are flags and what do they mean?
To assist you, the user, flags have been added to the Pending Cases screen so you
may see the geocode status of a case without opening any case information. An
absolute match, or a partial match selected as correct by the user, will flag
the case as having found an appropriate match for the address. Choosing a
centroid match will flag the case as having found a municipality, county, or zip
code centroid for the address. Any address that was not geocoded will have a
flag indicating that no match was found for the address.
This symbol indicates a match was found for the address
This symbol indicates a centroid match was found for the address
This symbol indicates that no match was found for the address
Sample Pending Case screen with flags added to the Last Name column to indicate the
geocode match status.