Take the 2-minute tour ×
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It's 100% free, no registration required.

Edit: Found this page detailing the standard geocoding abbreviation types which may be of use when trying to match foreign street types. It appears that we'll have to create a much more robust version.

The problem is as listed in the title: Our current geocoding attempts (using a proprietary list of addressed and a proprietary streets network) in Quebec are coming up with abysmal match rates (40-50% overall). We have tried looking at problems with characters sets and postal code inconsistencies, but nothing seems to be nailing it down. Presuming these two factors are not the issue, what suggestions might be offered as possible pitfalls when geocoding in this area?

Important notes:

    1. Geocoding with ArcGIS 10
    2. Using FSALDUs as post code in "ABC XYZ" format.

Here are some example addresses.

    ARC_Street          ARC_ZIP     CITY                           STATE
1134 BRIDGE ST W        A7R 3L1     NAPANEE                         ON
75 RUE PRINCIPALE       G0A 1A0     SAINTE-CHRISTINE-D'AUVERGNE     QC
43 RUE PRINCIPALE       G0A 1A0     SAINTE-CHRISTINE-D'AUVERGNE     QC
325 RANG SAINT-JACQUES  G0A 1A0     SAINTE-CHRISTINE-D'AUVERGNE     QC
325 SAINT-JACQUES RANG  G0A 1A0     SAINTE-CHRISTINE-D'AUVERGNE     QC
125 RUE PRINCIPALE      G0A 1A0     SAINTE-CHRISTINE-D'AUVERGNE     QC
168 RANG SAINTE-ANNE N  G0A 1A0     SAINTE-CHRISTINE-D'AUVERGNE     QC
168 RANG SAINTE-ANNE    G0A 1A0     SAINTE-CHRISTINE-D'AUVERGNE     QC
share|improve this question
    
It's not unusual to get only 50% match rates (with Census TIGER files) on the first attempt in rural areas in the US. How urbanized is the part of Quebec in which you are working? –  whuber Apr 27 '11 at 22:15
    
can you provide a sample address which gives a poor match? –  KHibma Apr 27 '11 at 22:21
    
@whuber It's the entirety of Quebec, so I'm not sure what the norm would be. –  Nathanus Apr 28 '11 at 0:33
1  
If those lines aren't somehow truncated, it seems you are missing postal codes from half of them. That alone would indicate you're only going to get about a 50% match: the codes are crucial. –  whuber Apr 28 '11 at 2:04
    
@whuber It is truncated. That field is a unique key built on the other fields. The Arc_ZIP has the postal codes. –  Nathanus Apr 28 '11 at 14:08
add comment

2 Answers

This is specific to Montreal and ArcGIS 9.3 but other than that it is almost what you are looking to achieve. It will not take much to modify it for ArcGIS 10.

"Sometimes, a prefix is not recognized. For example, CH meaning Chemin in French is interpreted by the program as Church. To put CH in the prefix, click the Modify button and make necessary changes. Select the right candidate and click Match. "

PDF file

http://www.mcgill.ca/files/library/geocoding9.pdf

share|improve this answer
    
Definitely worth looking into. Thank you. –  Nathanus Apr 28 '11 at 12:41
add comment

The postal codes beginning with 'G0A' are rural. If the second character is zero, it's rural and not very precise. As one GIS expert told me, 'Rural is the Achilles Heel of GIS.'

Over the last few years, Canada Post has been working diligently on improving their data and breaking up these rural codes into more precise codes. The main reason is that emergency services couldn't find the homes. I work for GreatData.com and we sell postal code level data with latitude and longitude and it has taken a huge effort to get these accurate. It's far more difficult to geocode the addresses, so we don't do that.

Here's a StackExchange link that should help you find another way to geocode.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.