topic Re: geocoding for intersecting streets in Data Management Questions

geocoding for intersecting streets

shay-geo — Wed, 01 Aug 2012 15:09:18 GMT

Hello ,

We were trying to set up a geocoder for intersecting streets.

We took the intersecting points from street file, which has the information to set up geocoder. Then we dissolved all points to get 2 points per intersection. We then combined street names like "COUCHMAN AVE & POPPY ST" into addressCombined (new field) to bring all intersecting street field to search upon?

Questions are -
1. Is this a right way to set up geocode service for intersections?
2. Can point file work to set up geocode for intersections and what Locator Style, i will have to use?
3. Can geocode for intersection work just on input as "COUCHMAN & POPPY" or it needs Zipcode or City also?

Thanks and Regards,
Shay ~

Re: geocoding for intersecting streets

JoeBorgione — Wed, 01 Aug 2012 17:35:49 GMT

Hello ,

We were trying to set up a geocoder for intersecting streets.

We took the intersecting points from street file, which has the information to set up geocoder. Then we dissolved all points to get 2 points per intersection. We then combined street names like "COUCHMAN AVE & POPPY ST" into addressCombined (new field) to bring all intersecting street field to search upon?

Questions are -
1. Is this a right way to set up geocode service for intersections?
2. Can point file work to set up geocode for intersections and what Locator Style, i will have to use?
3. Can geocode for intersection work just on input as "COUCHMAN & POPPY" or it needs Zipcode or City also?

Thanks and Regards,
Shay ~

1: It's one way to do it. I suspect you have two points because one is called Street A & Street B while the other is called Street B & Street A, right?

2: Yes you can use points; look here for a description of what types of locators are used with a specific feature type. Sometimes these single point type of locators are not very forgiving.

3. Personally, I just use a US Streets with alt names for geocoding for intersections. If the propper name is say E COCHMAN AVE and S POPPY ST, you need to have alias names that allow it to match with just Cochman & Poppy. You can also add your preffered intersection connectors: I like &, and, @....

Hope this helps

Re: geocoding for intersecting streets

shay-geo — Wed, 01 Aug 2012 23:10:44 GMT

Hello Joe,

Thank you for the response. It definitely helped.

We do have two points as you mentioned.

Will you be able to elaborate on # 3 please? As we tried to create a locator (from SDE point file) using US street style and having "combinedAddress" as primary address field. But no luck so far.

Also, Do all ESRI based Geocode services have [Zip code] a mandatory field?

Thanks and Regards,
Shay ~

1: It's one way to do it. I suspect you have two points because one is called Street A & Street B while the other is called Street B & Street A, right?

2: Yes you can use points; look here for a description of what types of locators are used with a specific feature type. Sometimes these single point type of locators are not very forgiving.

3. Personally, I just use a US Streets with alt names for geocoding for intersections. If the propper name is say E COCHMAN AVE and S POPPY ST, you need to have alias names that allow it to match with just Cochman & Poppy. You can also add your preffered intersection connectors: I like &, and, @....

Hope this helps

Re: geocoding for intersecting streets

JoeBorgione — Thu, 02 Aug 2012 12:08:01 GMT

Will you be able to elaborate on # 3 please? As we tried to create a locator (from SDE point file) using US street style and having "combinedAddress" as primary address field. But no luck so far.

Also, Do all ESRI based Geocode services have [Zip code] a mandatory field?

I can't see how you can use points in a us street style; that style of locator uses ranges for address interpolation. When using streets as the basis to match to, intersections are 'found' by actual geometric intersections of the features. So if Main St and Elm Ave intersect as features, you can get a hit by using Main ST & Elm Ave as the address. However, if Main St over passes I-80, you can not get a match with I-80 & Main St.

As far as aliases, that's an art in and of itself. Depending on how lazy your geocoding staff is, you'll need a varying degree of aliases. Out of the box, a 100% match for an intersection needs to be entered just as the streets are parsed in the locator. So if you define pre-dir, street-name, suf-dir street-type etc, you need to enter your intersections accordingly:

S MAIN ST & E ELM AVE

So your geocoding staff need to on their game.

But if you alias or use use a series of locators that don't parse out the components in a composite, you can get good results with:

MAIN & ELM

So the geocoding staff gets to be lazy.

As far as zip codes go, in all the years I've been geocoding and all the records I've geocoded (I work at two large 9-1-1 call centers) I've never used Zip Codes. City-Codes at times, but no zip codes. Your mileage may vary....

Hope this helps-

Re: geocoding for intersecting streets

AmySmith3 — Wed, 08 Aug 2012 19:28:42 GMT

When using streets as the basis to match to, intersections are 'found' by actual geometric intersections of the features. So if Main St and Elm Ave intersect as features, you can get a hit by using Main ST & Elm Ave as the address. However, if Main St over passes I-80, you can not get a match with I-80 & Main St.

Hi jborgion!

Do you happen to know if there's a way to create geometric intersections of street features where they don't currently exist? For example, say I want to geocode something to the point where Main St passes over I-80. I would need that to be considered an intersection in order to retrieve a match when geocoding "I-80 & Main St".

Any advice would be greatly appreciated!

Amy

Re: geocoding for intersecting streets

JoeBorgione — Thu, 09 Aug 2012 10:08:44 GMT

Hi jborgion!

Do you happen to know if there's a way to create geometric intersections of street features where they don't currently exist? For example, say I want to geocode something to the point where Main St passes over I-80. I would need that to be considered an intersection in order to retrieve a match when geocoding "I-80 & Main St".

Any advice would be greatly appreciated!

Amy

Amy- personally I think you are looking for trouble but yes it can be done; I actually found an old (very old, like 9 years) post of mine here. This is a link to the current Planarize Lines tool.

So why don't I like the idea? As GIS practitioners our job is to model features in geographic space as closely as we can to the real-world. Quite frankly, Main and I-80 DON'T intersect. Creating such an intersection compromises the data integrity. 😞

You may be geocoding against these features today, and next week your boss says 'Hey, whats this thing I read about called Network Analysis?' All of the sudden you are scrambling because your routes include the Main St overpass to I-80 connectivity. (Boss: 'Amy! How the h-e-double-hockey-stick did that delivery truck just drop 75 feet from Main to I-80?') :mad:

Also, consider that you've spent all this time getting your address ranges just the way you want them. You planarize the streets and instead of having one continuous line segment of Main St with a range of 100-500, you have TWO; each with the exact same range. Ouch. Back to (re)editing ranges! 😛

Depending on the number of non-intersections you are dealing with, you might consider creating a point feature class to depict them. My guess is you'll thank me in the morning! :rolleyes:

Hope this helps-

Re: geocoding for intersecting streets

AmySmith3 — Thu, 09 Aug 2012 14:55:04 GMT

My guess is you'll thank me in the morning!

Hi Joe,

First of all, yes! Thanks! I very much appreciate the sage advice, and I agree, it's important not to compromise the data just for the sake of results. I had actually been testing out the "Planarize" method, making sure to create a copy of my streets feature class before hand and clearly label it as "Planarized" (this would hopefully be a red flag for someone looking to create a network).

The thing I noticed about the planarize technique is that it works well when using the "Dual Ranges" address locator style, but not so well with the "Street Name" style. Do you have any ideas as to why this is?

Finally, I wanted to mention that the table I am working with does not include house numbers, but rather primary and secondary streets. The intersections act more as reference points than precise locations. For example, the primary street and secondary street may not technically intersect, but the space that the two streets share is a reference point for where an event occurred.

Thanks again for your help!

Take care,

Amy

Re: geocoding for intersecting streets

JoeBorgione — Thu, 09 Aug 2012 15:17:41 GMT

The thing I noticed about the planarize technique is that it works well when using the "Dual Ranges" address locator style, but not so well with the "Street Name" style. Do you have any ideas as to why this is?

I've never had occasion to to use the dual range type of locator; I'm a U.S Streets With Alt Name kind of guy. Not sure why it would work better.

Finally, I wanted to mention that the table I am working with does not include house numbers, but rather primary and secondary streets. The intersections act more as reference points than precise locations. For example, the primary street and secondary street may not technically intersect, but the space that the two streets share is a reference point for where an event occurred.

All the more reason to use points

Re: geocoding for intersecting streets

AmySmith3 — Thu, 09 Aug 2012 16:16:54 GMT

All the more reason to use points

Hi Joe,

I'm not sure I completely understand what you mean by using points (Sorry! I'm still learning the ins and outs of geocoding). :confused: Is there a way to use points as references in an address locator, and subsequently to geocode a table of intersections?

Thanks again for all of your help!

Amy

Re: geocoding for intersecting streets

JoeBorgione — Thu, 09 Aug 2012 17:20:14 GMT

Is there a way to use points as references in an address locator, and subsequently to geocode a table of intersections?

You bet. You need to create a point feature class. That's why I mentioned earlier 'depending on how many you have'; you are looking at creating a point (or two) for your faux intersections. See my attached image for clarification. I've added a couple of points to my point feature class; the attribute table is very simple; just one field called..... Location.

Notice that two of my locations are at over/underpasses, and I named them with respect to the freeway. This is where you might need two points, since it could be I-15 at Harrisville or Harrisville at I-15, right? You could also use an alias table but I'm not going to get into that. But the Pioneer Exchange is just that, and nothing else.

You would need to decide on a naming convention; that is really important since point based locators are typically not very forgiving. Take a look here for the various locator types and thier associated feature classes. I use the Single Field type very often for 'common place names'; I can resolve to a point location of various features like Business Names, Mile Markers, Picknick Areas, etc etc. So if my 'location' field is populated with "Amys Bar and Grill" I get match. If I type in "Joes House" I get a hit on it as well....

Hope this helps-

Re: geocoding for intersecting streets

AmySmith3 — Thu, 09 Aug 2012 17:38:15 GMT

You would need to decide on a naming convention; that is really important since point based locators are typically not very forgiving.

Wow! Thanks, Joe, this has been immensely helpful. I truly appreciate the time you've taken to respond to my questions on this forum.

My concern about the point you made above is that, because point based locators aren't as forgiving as other types of locators, many of the intersections in my table may not be matched. For example, if I have a point called "US Highway 1 & Orange Ave", and my table has an entry such as "hwy 1 & orange av", would a match be made, or does the table entry need to match the point name exactly?

Amy

Re: geocoding for intersecting streets

JoeBorgione — Thu, 09 Aug 2012 17:55:10 GMT

Regardless of locator type, it's always a good idea for naming conventions when you do a lot of geocoding. I work at two 9-1-1 call centers and I've made it my life's work to enforce conventions. I don't know how you are getting your address lists or who creates them, but your life will become increasingly easier and much less frustrating if you come up with some kind of convention. In my world it's AVE, not AV, not Avenue; It's HWY 1, not US 1 or US HWY 1; its S not So or South. You get the idea

It'll take some time and trust me who ever you are working with is going to whine and complain. Make up a few of your more popular sites; see how forgiving you can get the locator by adjusting the spelling sensitivty before you start getting false hits...

Re: geocoding for intersecting streets

AmySmith3 — Thu, 09 Aug 2012 18:09:59 GMT

Regardless of locator type, it's always a good idea for naming conventions when you do a lot of geocoding.

Fantastic advice! Much of the data I work with are from publicly accessible tables downloaded as text files from organizations' websites. They often requires a decent amount of cleanup. Luckily, it seems like there are some good techniques that can be used to impose conventions after-the-fact, such as the "Standardize Addresses" tool, or simply writing scripts to clean up text files.

By the way, at the moment I'm 85% through a geocode of 20,000+ records with a current unmatched rate of 4%. 😉

Take care,

Amy