topic Re: ARC10 Geocoding w Dual Ranges zone erroneous in Data Management Questions

ARC10 Geocoding w Dual Ranges zone erroneous

ccain — Mon, 25 Apr 2011 12:26:04 GMT

I am using ARC10 desktop with Service Pack 1 installed and am Working on the GISTutorial 1 Basic Workbook prior to teaching it. As part of the lesson a new address locator is made using Dual ranges comparing street address with zip codes. I have found that the address compare with a 95-100% match even though the zip codes are totally in error. As long as the street matches and a zip has five digits the match occurs.

I saw where this was an error NIM055232 supposedly fixed in Service Pack 1 but it is still not working correctly.

Re: ARC10 Geocoding w Dual Ranges zone erroneous

BradNiemand — Mon, 25 Apr 2011 19:12:00 GMT

NIM055232 fixes the opposite of the issue that you are having, no matches would occur if the locator is built without all of the zone fields mapped.

There is an issue where the score is higher than expected when a locator is built with not all of the zone fields mapped. Essentially, the locator assumes that, in your case, the city and the state field have a score of 100 and the zip has a score of 0. This increases the total score of the address and therefore can be a bit confusing.

There are a couple work-arounds that we can try and use if you would like. The first would just be to increase the minimum match score to something like 96. Another option would be for me to provide an updated style for you in which you could build your locator from.

Just let me know what works best for you and sorry for the inconvenience.

Brad

Re: ARC10 Geocoding w Dual Ranges zone erroneous

ccain — Mon, 25 Apr 2011 19:47:48 GMT

NIM055232 fixes the opposite of the issue that you are having, no matches would occur if the locator is built without all of the zone fields mapped.

There is an issue where the score is higher than expected when a locator is built with not all of the zone fields mapped. Essentially, the locator assumes that, in your case, the city and the state field have a score of 100 and the zip has a score of 0. This increases the total score of the address and therefore can be a bit confusing.

There are a couple work-arounds that we can try and use if you would like. The first would just be to increase the minimum match score to something like 96. Another option would be for me to provide an updated style for you in which you could build your locator from.

Just let me know what works best for you and sorry for the inconvenience.

Brad

I am not sure I exactly understand what you are saying. When I set up the Address locator my Reference Data feature [Pittsburgh streets] did not have a field for State and City and the Field Map defaults to <none>. If I understand you correctly you are saying that because the field map is <none> it takes this as a higher value or 100 match and ignores the zip. Thus as long as there is a 5 digit zip in the zip field it will match. [Those addresses with only four digits in the zip field failed]

Charlotte

Re: ARC10 Geocoding w Dual Ranges zone erroneous

BradNiemand — Mon, 25 Apr 2011 20:09:20 GMT

Yes you are correct. The minimum match score out of the box is set to 85 so because of the issue of the unmapped fields, in your case city and state, you will get matches for 5 digit zip codes entered that are incorrect.

One work-around is setting the minimum match score of the locator to a higher value like 96. The other would be to modify style to help alleviate the issue.

Brad

Re: ARC10 Geocoding w Dual Ranges zone erroneous

ccain — Mon, 25 Apr 2011 20:17:19 GMT

Okay, How do I modify the style? Create a new field in my reference data for State and city and set it to zero?

Charlotte

Re: ARC10 Geocoding w Dual Ranges zone erroneous

BradNiemand — Mon, 25 Apr 2011 21:06:51 GMT

I can update the style for you. Would you like the score to be much lower or not return anything at all?

Brad

Re: ARC10 Geocoding w Dual Ranges zone erroneous

ccain — Tue, 26 Apr 2011 12:38:39 GMT

The score should be lowered.
In this case I am trying to teach how to find the errors and evaluate them plus how to use the geolocator. Although I think the way the zipcode is ignored is an error. You cannot assume that the address you are trying to locate is in the range of the geolocator. For instance if you were trying to geolocate participants at a local event, you could get participants from out of state thus with a valid zipcode that should not match to your locator.

Re: ARC10 Geocoding w Dual Ranges zone erroneous

BradNiemand — Tue, 26 Apr 2011 17:49:41 GMT

The score should be lowered.
In this case I am trying to teach how to find the errors and evaluate them plus how to use the geolocator. Although I think the way the zipcode is ignored is an error. You cannot assume that the address you are trying to locate is in the range of the geolocator. For instance if you were trying to geolocate participants at a local event, you could get participants from out of state thus with a valid zipcode that should not match to your locator.

A correction to your statement above. The problem isn't that the zipcode is ignored, it is that the city and state are not ignored. Let me clarify. With zones (city, state, and zip), the locator tries first to search for the zip in the dictionary (think of the dictionary as exact match even though that is not exactly true). If the zip is found, then it uses city and state ONLY for scoring, not for restricting search. It then tries to find the street in this zipcode. If the final score of the search is higher than the minimum match score, then it will stop and return the matched address. If not, it will try to search for the city and state in the dictionary and use zipcode only for scoring.

So what happens is that the first search fails because there is no street in that zipcode that matches higher than the minimum match score. Therefore the locator "falls back" to the city and state. What happens is the locator compares "empty city" and "empty state" to empty dictionary and therefore matches. It then reduces the score because the zipcode is wrong but the score is not reduced by very much because it thinks that the city and state are correct in this case and gives them both a score of 100.

I have attached a style that does not include city and state that will give you some better results for now.

Re: ARC10 Geocoding w Dual Ranges zone erroneous

ccain — Tue, 26 Apr 2011 19:42:05 GMT

Thank you Brad for the style and for the extra explanation. I now see why it is doing it this way. I appreciate it.

Charlotte Cain

Re: ARC10 Geocoding w Dual Ranges zone erroneous

AndrewMaracini1 — Wed, 04 May 2011 12:16:56 GMT

I'm having an issue as well. I have a table with From To, Street Address, City, State, but no zip. When I run the built-in US Streets Geocoder I get a match of about 72%. When I try to create my own locator with dual ranges it fails completely with 0 matches. I've tried using different fields for my street address to no avail. I'm attaching a small subset of the data for your review.

thanks,

Andy

Re: ARC10 Geocoding w Dual Ranges zone erroneous

BradNiemand — Wed, 04 May 2011 15:21:59 GMT

Can you try the attached style and let me know if this helps? This style will work with 10.0 and 10.0 SP1. Let me know if you need it for 10.0 SP2 because there are some improvements in there that I can't include if you use 10.0 or 10.0 SP1.

Re: ARC10 Geocoding w Dual Ranges zone erroneous

AndrewMaracini1 — Mon, 09 May 2011 12:28:38 GMT

Brad,

Thanks for the help. Can you please tell me how to load the style you created?

Andy

Re: ARC10 Geocoding w Dual Ranges zone erroneous

BradNiemand — Mon, 09 May 2011 15:20:29 GMT

Unzip and put the lot.xml file in your <ArcGIS Install>\Locators folder.

Brad

Re: ARC10 Geocoding w Dual Ranges zone erroneous

AndrewMaracini1 — Mon, 09 May 2011 16:12:19 GMT

Brad,

Thanks, still 100% unmatched. I used: "US Address with City State - Dual Ranges". Is that the style you provided? What could I be doing wrong? Its weird because as I said before when I use the Road shapefile with the US Streets geocoder I get about 72%, I'm just trying to improve my results.

I created a single locator using fire hydrants and got 79% which is better but ultimately I'd like to create a composite of dual range streets and fire hydrants.

Re: ARC10 Geocoding w Dual Ranges zone erroneous

BradNiemand — Mon, 09 May 2011 16:16:03 GMT

Are you able to share your data with me to test? You can send it to me.

Brad
bniemand@esri.com

Re: ARC10 Geocoding w Dual Ranges zone erroneous

AndrewMaracini1 — Mon, 09 May 2011 17:48:16 GMT

Sure, I'll send it to your email.

Thanks!

Re: ARC10 Geocoding w Dual Ranges zone erroneous

AndrewMaracini1 — Tue, 10 May 2011 17:58:29 GMT

Brad,

Thanks for your help in identifying several issues with the data and that I needed SP 2 as well as the patch for SP 2 to resolve my issue of no matches. I'm extremely pleased with the results and your prompt response.

Andy