Geocoding Interstate and Highway exits

RobertScheitlin__GISP — Thu, 10 Nov 2011 14:52:47 GMT

All,

I am looking for best practice for setting up my locator to handle interstate and Highway exit numbers, i.e "I-20 @ exit 465" I currently have a composite locator that is a Point Single Address and Lot and then it goes to my US Streets with City, State and Zip. And Help or suggestions would be appreciated. I am willing to create any reference data that I might need if my centerline data for the interstate and Highways is not the route to go.

Re: Geocoding Interstate and Highway exits

JoeBorgione — Fri, 11 Nov 2011 21:40:07 GMT

All,

I am looking for best practice for setting up my locator to handle interstate and Highway exit numbers, i.e "I-20 @ exit 465" I currently have a composite locator that is a Point Single Address and Lot and then it goes to my US Streets with City, State and Zip. And Help or suggestions would be appreciated. I am willing to create any reference data that I might need if my centerline data for the interstate and Highways is not the route to go.

I don't know about best practice, but this is what I have done in the past:

Freeways in urban areas: I address them just like the local grid. For example 4500 S I-15 SB FWY. For my freeways, this puts the point right on the 4500 South overpass...

Freeways in rural areas: use the mile markers as the basis for your address ranges. Give yourself enough 'room' for decimal miles. For example, I recently took a care of a short segment of freeway that goes from MM 81 through MM 112, so the address range is 810-1120. Address 955 is at mile post 95.5 etc.

Mile Posts; I'm lucky that I can get good point data for mileposts, so I use them as a point feature class like MM 293 I-15 SB FWY or MM 9 HWY 201 etc

Exits I do the same thing: Exit 293 I-15 SB FWY or Exit 293 I-15 NB FWY. For exits, I take the location where the off ramp diverges from the main flow.

On ramps/Off ramps can be ranged 1-3, 2-4 if you need to. That gets confusing for people other than gis-geocode people. I work in 9-1-1 dispatch and it's a really tough sell for dispatchers to imagine four houses along an on ramp with houses 1 and 3 on one side and 2 and 4 on the other....

If you don't have a special need to address range freeways, I'd say stick to point references for everything. You get a little leeway when it comes to locations along freeways.

Hope this isn't rambling too much and you find it helpful!

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Geocoding Interstate and Highway exits

Re: Geocoding Interstate and Highway exits