Concept: Geocoding Addresses: Using ArcView
Last Updated: 2001-07-31
There are occasions when the location of items may want to be mapped and inspected visually. There are also occasions when one may want to conduct small area analyses on the City of Winnipeg, as in the WRHA report
(Frohlich, Fransoo, & Roos, 2001
). This requires that the location of various items can be identified at the postal code level. However, if all one has are addresses without postal codes, then the following steps can be taken to assign postal codes to these addresses.
The program ArcView is used to accomplish these goals. One can map the location of items in Winnipeg or Manitoba, and also use the program to assign postal codes to items that have been geocoded.
The set of addresses to be geocoded should be in a tab-delimited text file with field headers. The name of the field should contain 'address', just to make things easier.
Open the file containing the addresses by clicking on the
and then pressing the
- In the window that pops up, locate the file, and press OK . The table with the list of addresses should now appear.
Under View, click on
and locate the file.
After the SNF is added, under the View menu, select
. The Address Style should be 'US Streets' (i.e. the street number is followed by a space and then the street name, as in the above table)
Identify the table containing the addresses, and the field in which the addresses are located. There are several options at this point.
option is preferable.
. ArcView will automatically assign locations to all addresses that are straightforward.
Addresses for which there are a number of good candidate matches, or for which the street is misspelled or does not appear in the SNF will not be matched.
- Addresses with room or apartment numbers prior to the street number, as in the entry for the West Broadway Community Church above, will also fail.
- Addresses for which there are a number of good candidate matches, or for which the street is misspelled or does not appear in the SNF will not be matched.
- When ArcView has completed this process, press Done . Both the number of matches (i.e. addresses that have been successfully geocoded) and the number of 'No Matches' will be displayed.
- The Interactive Match option is preferable.
and adjust the following tolerances:
Minimum Match Score
'Minimum score to be considered a candidate'
. Lowering these numbers will affect the matching process. The first might permit some misspelled street names to be found. The second might assign addresses that were not previously considered. The third will identify candidates that may not have been considered on the first round.
- Then press Start . ArcView will go through the No Matches again using the new settings.
Do not press Start, do not adjust Preferences. Each address will appear one at a time in the window with a list of candidates identified by ArcView below (there may be none!).
If the appropriate location is in the list, then highlight it and press
. If the location is not in the list, press
to change either the house number or street name, or street suffix (e.g., ST, AV, CR, etc.) to find a match.
- E.g. Addresses on Portage will not be identified if the street suffix is AVE rather than AV. Changing this one field will allow the location to be identified.
If the right candidate appears, choose it.
If no candidates appear despite all your alterations, then press
to skip the address and move on.
, when completed.
- Press Done again to exit the geocoding application.
- If no candidates appear despite all your alterations, then press Next to skip the address and move on.
- If the appropriate location is in the list, then highlight it and press Match . If the location is not in the list, press Edit/Standardize to change either the house number or street name, or street suffix (e.g., ST, AV, CR, etc.) to find a match.
To save this (in order to print), under the File menu, choose
- Choose a file name and specify the location for it to be saved.
|Winnipeg Native Alliance||Non-profit||185 Young Street||Girls Group|
|Winnipeg Native Alliance||Non-profit||185 Young Street||Cooking Club|
|Winnipeg Native Alliance||Non-profit||185 Young Street||
Activities at YM-YWCA
|West Broadway Community Church||Non-profit||102-222 Furby Street||Family Drop-in|
|Art City||Non-profit||616 Broadway||Art Program|
|Contemporary Dancers||Non-profit||109 Pulford Street||Dance Instruction|
|Inner City Youth Alive Inc.||Non-profit||418 Aberdeen Avenue||Youth Clubs|
|Inner City Youth Alive Inc.||Non-profit||418 Aberdeen Avenue||Youth Drop-In Program|
|Inner City Youth Alive Inc.||Non-profit||418 Aberdeen Avenue||Winter Camp Trip|
|Inner City Youth Alive Inc.||Non-profit||418 Aberdeen Avenue||Energy Club Leadership Dev. Prog.|
|Winnipeg Boys & Girls Club||Non-profit||929 Main Street||PEP Program|
|Wolseley Family Place||Non-profit||691 Wolseley Avenue||Family Resource Centre|
In ArcView :
ArcView can now be used to assign a geospatial location to the set of addresses, using Statistics Canada's Street Network File (MCHP programmers see Charles Burchill to access this file).
You now have the option to do an 'Interactive Re-match'. There are two things that can be done at this step:
1) Change the preferences for the matching procedure.
2) If there are relatively few No Matches, this procedure will be the one to follow.
Click on 'Attributes of Geocd1.shp' , which will now appear in the View window. This will make the points for the newly geocoded addresses appear in the View.
For assigning Postal Codes:
A table called 'Attributes of Geocd1.shp' should now exist.
Click on the window for this table to make it the active window in ArcView.
- Under the 'Theme' menu, choose Add XY .
Under the View menu, click
and find the Statistics Canada Postal Code Conversion file (MCHP programmers - please see Charles to access this file). The following will appear: Winnipeg streets, a series of points representing the programs, and a series of points representing the postal codes.
Under the View menu, click on
Choose the final option,
Assign Data by Location
and click on
Under 'Select a Theme to Assign Data to', choose the file,
Under 'Select a theme to assign data from', choose
the postal code file
- Click Finish . When this is done, postal codes will have been added to the 'Attributes of Geocd1.shp' Table which also contains all the information in the original table or addresses.
- Choose the final option, Assign Data by Location and click on Next .
Click on the table
- Under the File menu, choose Export . Choose the File Type and Location, give it an appropriate name, and save the file.
- Consult Neighbourhood Clusters (prior name Neighbourhood Resource Networks (NRN))' to execute this step.
The postal code file should now be added to the View.
To export this file:
For assigning the CA's and NRN's from the file with postal codes, HealthSys and SAS must be used. Place the file into an appropriate folder in HealthSys.
- Frohlich N, Fransoo R, Roos NP. Indicators of Health Status and Health Service Use for the Winnipeg Regional Health Authority. Winnipeg, MB: Manitoba Centre for Health Policy, 2001. [Report] [Summary] (View)
- postal codes
Manitoba Centre for Health Policy
Community Health Sciences, Max Rady College of Medicine,
Rady Faculty of Health Sciences,
Room 408-727 McDermot Ave.
University of Manitoba
Winnipeg, MB R3E 3P5 Canada